/* * drm_irq.c IRQ and vblank support * * \author Rickard E. (Rik) Faith * \author Gareth Hughes */ /* * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com * * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas. * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include #include "drm_trace.h" #include /* For task queue support */ #include #include #include /* Access macro for slots in vblank timestamp ringbuffer. */ #define vblanktimestamp(dev, crtc, count) \ ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE]) /* Retry timestamp calculation up to 3 times to satisfy * drm_timestamp_precision before giving up. */ #define DRM_TIMESTAMP_MAXRETRIES 3 /* Threshold in nanoseconds for detection of redundant * vblank irq in drm_handle_vblank(). 1 msec should be ok. */ #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 /* * Clear vblank timestamp buffer for a crtc. */ static void clear_vblank_timestamps(struct drm_device *dev, int crtc) { memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time)); } /* * Disable vblank irq's on crtc, make sure that last vblank count * of hardware and corresponding consistent software vblank counter * are preserved, even if there are any spurious vblank irq's after * disable. */ static void vblank_disable_and_save(struct drm_device *dev, int crtc) { unsigned long irqflags; u32 vblcount; s64 diff_ns; int vblrc; struct timeval tvblank; int count = DRM_TIMESTAMP_MAXRETRIES; /* Prevent vblank irq processing while disabling vblank irqs, * so no updates of timestamps or count can happen after we've * disabled. Needed to prevent races in case of delayed irq's. */ spin_lock_irqsave(&dev->vblank_time_lock, irqflags); dev->driver->disable_vblank(dev, crtc); dev->vblank[crtc].enabled = false; /* No further vblank irq's will be processed after * this point. Get current hardware vblank count and * vblank timestamp, repeat until they are consistent. * * FIXME: There is still a race condition here and in * drm_update_vblank_count() which can cause off-by-one * reinitialization of software vblank counter. If gpu * vblank counter doesn't increment exactly at the leading * edge of a vblank interval, then we can lose 1 count if * we happen to execute between start of vblank and the * delayed gpu counter increment. */ do { dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc); vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); } while (dev->vblank[crtc].last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc); if (!count) vblrc = 0; /* Compute time difference to stored timestamp of last vblank * as updated by last invocation of drm_handle_vblank() in vblank irq. */ vblcount = atomic_read(&dev->vblank[crtc].count); diff_ns = timeval_to_ns(&tvblank) - timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); /* If there is at least 1 msec difference between the last stored * timestamp and tvblank, then we are currently executing our * disable inside a new vblank interval, the tvblank timestamp * corresponds to this new vblank interval and the irq handler * for this vblank didn't run yet and won't run due to our disable. * Therefore we need to do the job of drm_handle_vblank() and * increment the vblank counter by one to account for this vblank. * * Skip this step if there isn't any high precision timestamp * available. In that case we can't account for this and just * hope for the best. */ if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { atomic_inc(&dev->vblank[crtc].count); smp_mb__after_atomic(); } /* Invalidate all timestamps while vblank irq's are off. */ clear_vblank_timestamps(dev, crtc); spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); } static void vblank_disable_fn(unsigned long arg) { struct drm_vblank_crtc *vblank = (void *)arg; struct drm_device *dev = vblank->dev; unsigned long irqflags; int crtc = vblank->crtc; if (!dev->vblank_disable_allowed) return; spin_lock_irqsave(&dev->vbl_lock, irqflags); if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) { DRM_DEBUG("disabling vblank on crtc %d\n", crtc); vblank_disable_and_save(dev, crtc); } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } /** * drm_vblank_cleanup - cleanup vblank support * @dev: DRM device * * This function cleans up any resources allocated in drm_vblank_init. */ void drm_vblank_cleanup(struct drm_device *dev) { int crtc; /* Bail if the driver didn't call drm_vblank_init() */ if (dev->num_crtcs == 0) return; for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer); vblank_disable_fn((unsigned long)&dev->vblank[crtc]); } kfree(dev->vblank); dev->num_crtcs = 0; } EXPORT_SYMBOL(drm_vblank_cleanup); /** * drm_vblank_init - initialize vblank support * @dev: drm_device * @num_crtcs: number of crtcs supported by @dev * * This function initializes vblank support for @num_crtcs display pipelines. * * Returns: * Zero on success or a negative error code on failure. */ int drm_vblank_init(struct drm_device *dev, int num_crtcs) { int i, ret = -ENOMEM; spin_lock_init(&dev->vbl_lock); spin_lock_init(&dev->vblank_time_lock); dev->num_crtcs = num_crtcs; dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL); if (!dev->vblank) goto err; for (i = 0; i < num_crtcs; i++) { dev->vblank[i].dev = dev; dev->vblank[i].crtc = i; init_waitqueue_head(&dev->vblank[i].queue); setup_timer(&dev->vblank[i].disable_timer, vblank_disable_fn, (unsigned long)&dev->vblank[i]); } DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n"); /* Driver specific high-precision vblank timestamping supported? */ if (dev->driver->get_vblank_timestamp) DRM_INFO("Driver supports precise vblank timestamp query.\n"); else DRM_INFO("No driver support for vblank timestamp query.\n"); dev->vblank_disable_allowed = false; return 0; err: drm_vblank_cleanup(dev); return ret; } EXPORT_SYMBOL(drm_vblank_init); static void drm_irq_vgaarb_nokms(void *cookie, bool state) { struct drm_device *dev = cookie; if (dev->driver->vgaarb_irq) { dev->driver->vgaarb_irq(dev, state); return; } if (!dev->irq_enabled) return; if (state) { if (dev->driver->irq_uninstall) dev->driver->irq_uninstall(dev); } else { if (dev->driver->irq_preinstall) dev->driver->irq_preinstall(dev); if (dev->driver->irq_postinstall) dev->driver->irq_postinstall(dev); } } /** * drm_irq_install - install IRQ handler * @dev: DRM device * @irq: IRQ number to install the handler for * * Initializes the IRQ related data. Installs the handler, calling the driver * irq_preinstall() and irq_postinstall() functions before and after the * installation. * * This is the simplified helper interface provided for drivers with no special * needs. Drivers which need to install interrupt handlers for multiple * interrupts must instead set drm_device->irq_enabled to signal the DRM core * that vblank interrupts are available. * * Returns: * Zero on success or a negative error code on failure. */ int drm_irq_install(struct drm_device *dev, int irq) { int ret; unsigned long sh_flags = 0; if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) return -EINVAL; if (irq == 0) return -EINVAL; /* Driver must have been initialized */ if (!dev->dev_private) return -EINVAL; if (dev->irq_enabled) return -EBUSY; dev->irq_enabled = true; DRM_DEBUG("irq=%d\n", irq); /* Before installing handler */ if (dev->driver->irq_preinstall) dev->driver->irq_preinstall(dev); /* Install handler */ if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED)) sh_flags = IRQF_SHARED; ret = request_irq(irq, dev->driver->irq_handler, sh_flags, dev->driver->name, dev); if (ret < 0) { dev->irq_enabled = false; return ret; } if (!drm_core_check_feature(dev, DRIVER_MODESET)) vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL); /* After installing handler */ if (dev->driver->irq_postinstall) ret = dev->driver->irq_postinstall(dev); if (ret < 0) { dev->irq_enabled = false; if (!drm_core_check_feature(dev, DRIVER_MODESET)) vga_client_register(dev->pdev, NULL, NULL, NULL); free_irq(irq, dev); } else { dev->irq = irq; } return ret; } EXPORT_SYMBOL(drm_irq_install); /** * drm_irq_uninstall - uninstall the IRQ handler * @dev: DRM device * * Calls the driver's irq_uninstall() function and unregisters the IRQ handler. * This should only be called by drivers which used drm_irq_install() to set up * their interrupt handler. Other drivers must only reset * drm_device->irq_enabled to false. * * Note that for kernel modesetting drivers it is a bug if this function fails. * The sanity checks are only to catch buggy user modesetting drivers which call * the same function through an ioctl. * * Returns: * Zero on success or a negative error code on failure. */ int drm_irq_uninstall(struct drm_device *dev) { unsigned long irqflags; bool irq_enabled; int i; if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) return -EINVAL; irq_enabled = dev->irq_enabled; dev->irq_enabled = false; /* * Wake up any waiters so they don't hang. */ if (dev->num_crtcs) { spin_lock_irqsave(&dev->vbl_lock, irqflags); for (i = 0; i < dev->num_crtcs; i++) { wake_up(&dev->vblank[i].queue); dev->vblank[i].enabled = false; dev->vblank[i].last = dev->driver->get_vblank_counter(dev, i); } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } if (!irq_enabled) return -EINVAL; DRM_DEBUG("irq=%d\n", dev->irq); if (!drm_core_check_feature(dev, DRIVER_MODESET)) vga_client_register(dev->pdev, NULL, NULL, NULL); if (dev->driver->irq_uninstall) dev->driver->irq_uninstall(dev); free_irq(dev->irq, dev); return 0; } EXPORT_SYMBOL(drm_irq_uninstall); /* * IRQ control ioctl. * * \param inode device inode. * \param file_priv DRM file private. * \param cmd command. * \param arg user argument, pointing to a drm_control structure. * \return zero on success or a negative number on failure. * * Calls irq_install() or irq_uninstall() according to \p arg. */ int drm_control(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_control *ctl = data; int ret = 0, irq; /* if we haven't irq we fallback for compatibility reasons - * this used to be a separate function in drm_dma.h */ if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) return 0; if (drm_core_check_feature(dev, DRIVER_MODESET)) return 0; /* UMS was only ever support on pci devices. */ if (WARN_ON(!dev->pdev)) return -EINVAL; switch (ctl->func) { case DRM_INST_HANDLER: irq = dev->pdev->irq; if (dev->if_version < DRM_IF_VERSION(1, 2) && ctl->irq != irq) return -EINVAL; mutex_lock(&dev->struct_mutex); ret = drm_irq_install(dev, irq); mutex_unlock(&dev->struct_mutex); return ret; case DRM_UNINST_HANDLER: mutex_lock(&dev->struct_mutex); ret = drm_irq_uninstall(dev); mutex_unlock(&dev->struct_mutex); return ret; default: return -EINVAL; } } /** * drm_calc_timestamping_constants - calculate vblank timestamp constants * @crtc: drm_crtc whose timestamp constants should be updated. * @mode: display mode containing the scanout timings * * Calculate and store various constants which are later * needed by vblank and swap-completion timestamping, e.g, * by drm_calc_vbltimestamp_from_scanoutpos(). They are * derived from CRTC's true scanout timing, so they take * things like panel scaling or other adjustments into account. */ void drm_calc_timestamping_constants(struct drm_crtc *crtc, const struct drm_display_mode *mode) { int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0; int dotclock = mode->crtc_clock; /* Valid dotclock? */ if (dotclock > 0) { int frame_size = mode->crtc_htotal * mode->crtc_vtotal; /* * Convert scanline length in pixels and video * dot clock to line duration, frame duration * and pixel duration in nanoseconds: */ pixeldur_ns = 1000000 / dotclock; linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock); framedur_ns = div_u64((u64) frame_size * 1000000, dotclock); /* * Fields of interlaced scanout modes are only half a frame duration. */ if (mode->flags & DRM_MODE_FLAG_INTERLACE) framedur_ns /= 2; } else DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n", crtc->base.id); crtc->pixeldur_ns = pixeldur_ns; crtc->linedur_ns = linedur_ns; crtc->framedur_ns = framedur_ns; DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n", crtc->base.id, mode->crtc_htotal, mode->crtc_vtotal, mode->crtc_vdisplay); DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n", crtc->base.id, dotclock, framedur_ns, linedur_ns, pixeldur_ns); } EXPORT_SYMBOL(drm_calc_timestamping_constants); /** * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper * @dev: DRM device * @crtc: Which CRTC's vblank timestamp to retrieve * @max_error: Desired maximum allowable error in timestamps (nanosecs) * On return contains true maximum error of timestamp * @vblank_time: Pointer to struct timeval which should receive the timestamp * @flags: Flags to pass to driver: * 0 = Default, * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler * @refcrtc: CRTC which defines scanout timing * @mode: mode which defines the scanout timings * * Implements calculation of exact vblank timestamps from given drm_display_mode * timings and current video scanout position of a CRTC. This can be called from * within get_vblank_timestamp() implementation of a kms driver to implement the * actual timestamping. * * Should return timestamps conforming to the OML_sync_control OpenML * extension specification. The timestamp corresponds to the end of * the vblank interval, aka start of scanout of topmost-leftmost display * pixel in the following video frame. * * Requires support for optional dev->driver->get_scanout_position() * in kms driver, plus a bit of setup code to provide a drm_display_mode * that corresponds to the true scanout timing. * * The current implementation only handles standard video modes. It * returns as no operation if a doublescan or interlaced video mode is * active. Higher level code is expected to handle this. * * Returns: * Negative value on error, failure or if not supported in current * video mode: * * -EINVAL - Invalid CRTC. * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. * -ENOTSUPP - Function not supported in current display mode. * -EIO - Failed, e.g., due to failed scanout position query. * * Returns or'ed positive status flags on success: * * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping. * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval. * */ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, int *max_error, struct timeval *vblank_time, unsigned flags, const struct drm_crtc *refcrtc, const struct drm_display_mode *mode) { ktime_t stime, etime, mono_time_offset; struct timeval tv_etime; int vbl_status; int vpos, hpos, i; int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; bool invbl; if (crtc < 0 || crtc >= dev->num_crtcs) { DRM_ERROR("Invalid crtc %d\n", crtc); return -EINVAL; } /* Scanout position query not supported? Should not happen. */ if (!dev->driver->get_scanout_position) { DRM_ERROR("Called from driver w/o get_scanout_position()!?\n"); return -EIO; } /* Durations of frames, lines, pixels in nanoseconds. */ framedur_ns = refcrtc->framedur_ns; linedur_ns = refcrtc->linedur_ns; pixeldur_ns = refcrtc->pixeldur_ns; /* If mode timing undefined, just return as no-op: * Happens during initial modesetting of a crtc. */ if (framedur_ns == 0) { DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc); return -EAGAIN; } /* Get current scanout position with system timestamp. * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times * if single query takes longer than max_error nanoseconds. * * This guarantees a tight bound on maximum error if * code gets preempted or delayed for some reason. */ for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { /* * Get vertical and horizontal scanout position vpos, hpos, * and bounding timestamps stime, etime, pre/post query. */ vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos, &hpos, &stime, &etime); /* * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if * CLOCK_REALTIME is requested. */ if (!drm_timestamp_monotonic) mono_time_offset = ktime_get_monotonic_offset(); /* Return as no-op if scanout query unsupported or failed. */ if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n", crtc, vbl_status); return -EIO; } /* Compute uncertainty in timestamp of scanout position query. */ duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); /* Accept result with < max_error nsecs timing uncertainty. */ if (duration_ns <= *max_error) break; } /* Noisy system timing? */ if (i == DRM_TIMESTAMP_MAXRETRIES) { DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n", crtc, duration_ns/1000, *max_error/1000, i); } /* Return upper bound of timestamp precision error. */ *max_error = duration_ns; /* Check if in vblank area: * vpos is >=0 in video scanout area, but negative * within vblank area, counting down the number of lines until * start of scanout. */ invbl = vbl_status & DRM_SCANOUTPOS_INVBL; /* Convert scanout position into elapsed time at raw_time query * since start of scanout at first display scanline. delta_ns * can be negative if start of scanout hasn't happened yet. */ delta_ns = vpos * linedur_ns + hpos * pixeldur_ns; if (!drm_timestamp_monotonic) etime = ktime_sub(etime, mono_time_offset); /* save this only for debugging purposes */ tv_etime = ktime_to_timeval(etime); /* Subtract time delta from raw timestamp to get final * vblank_time timestamp for end of vblank. */ if (delta_ns < 0) etime = ktime_add_ns(etime, -delta_ns); else etime = ktime_sub_ns(etime, delta_ns); *vblank_time = ktime_to_timeval(etime); DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n", crtc, (int)vbl_status, hpos, vpos, (long)tv_etime.tv_sec, (long)tv_etime.tv_usec, (long)vblank_time->tv_sec, (long)vblank_time->tv_usec, duration_ns/1000, i); vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; if (invbl) vbl_status |= DRM_VBLANKTIME_INVBL; return vbl_status; } EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); static struct timeval get_drm_timestamp(void) { ktime_t now; now = ktime_get(); if (!drm_timestamp_monotonic) now = ktime_sub(now, ktime_get_monotonic_offset()); return ktime_to_timeval(now); } /** * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent * vblank interval * @dev: DRM device * @crtc: which CRTC's vblank timestamp to retrieve * @tvblank: Pointer to target struct timeval which should receive the timestamp * @flags: Flags to pass to driver: * 0 = Default, * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler * * Fetches the system timestamp corresponding to the time of the most recent * vblank interval on specified CRTC. May call into kms-driver to * compute the timestamp with a high-precision GPU specific method. * * Returns zero if timestamp originates from uncorrected do_gettimeofday() * call, i.e., it isn't very precisely locked to the true vblank. * * Returns: * Non-zero if timestamp is considered to be very precise, zero otherwise. */ u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, struct timeval *tvblank, unsigned flags) { int ret; /* Define requested maximum error on timestamps (nanoseconds). */ int max_error = (int) drm_timestamp_precision * 1000; /* Query driver if possible and precision timestamping enabled. */ if (dev->driver->get_vblank_timestamp && (max_error > 0)) { ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, tvblank, flags); if (ret > 0) return (u32) ret; } /* GPU high precision timestamp query unsupported or failed. * Return current monotonic/gettimeofday timestamp as best estimate. */ *tvblank = get_drm_timestamp(); return 0; } EXPORT_SYMBOL(drm_get_last_vbltimestamp); /** * drm_vblank_count - retrieve "cooked" vblank counter value * @dev: DRM device * @crtc: which counter to retrieve * * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. * * Returns: * The software vblank counter. */ u32 drm_vblank_count(struct drm_device *dev, int crtc) { if (WARN_ON(crtc >= dev->num_crtcs)) return 0; return atomic_read(&dev->vblank[crtc].count); } EXPORT_SYMBOL(drm_vblank_count); /** * drm_vblank_count_and_time - retrieve "cooked" vblank counter value * and the system timestamp corresponding to that vblank counter value. * * @dev: DRM device * @crtc: which counter to retrieve * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. * * Fetches the "cooked" vblank count value that represents the number of * vblank events since the system was booted, including lost events due to * modesetting activity. Returns corresponding system timestamp of the time * of the vblank interval that corresponds to the current vblank counter value. */ u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, struct timeval *vblanktime) { u32 cur_vblank; if (WARN_ON(crtc >= dev->num_crtcs)) return 0; /* Read timestamp from slot of _vblank_time ringbuffer * that corresponds to current vblank count. Retry if * count has incremented during readout. This works like * a seqlock. */ do { cur_vblank = atomic_read(&dev->vblank[crtc].count); *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); smp_rmb(); } while (cur_vblank != atomic_read(&dev->vblank[crtc].count)); return cur_vblank; } EXPORT_SYMBOL(drm_vblank_count_and_time); static void send_vblank_event(struct drm_device *dev, struct drm_pending_vblank_event *e, unsigned long seq, struct timeval *now) { WARN_ON_SMP(!spin_is_locked(&dev->event_lock)); e->event.sequence = seq; e->event.tv_sec = now->tv_sec; e->event.tv_usec = now->tv_usec; list_add_tail(&e->base.link, &e->base.file_priv->event_list); wake_up_interruptible(&e->base.file_priv->event_wait); trace_drm_vblank_event_delivered(e->base.pid, e->pipe, e->event.sequence); } /** * drm_send_vblank_event - helper to send vblank event after pageflip * @dev: DRM device * @crtc: CRTC in question * @e: the event to send * * Updates sequence # and timestamp on event, and sends it to userspace. * Caller must hold event lock. */ void drm_send_vblank_event(struct drm_device *dev, int crtc, struct drm_pending_vblank_event *e) { struct timeval now; unsigned int seq; if (crtc >= 0) { seq = drm_vblank_count_and_time(dev, crtc, &now); } else { seq = 0; now = get_drm_timestamp(); } e->pipe = crtc; send_vblank_event(dev, e, seq, &now); } EXPORT_SYMBOL(drm_send_vblank_event); /** * drm_update_vblank_count - update the master vblank counter * @dev: DRM device * @crtc: counter to update * * Call back into the driver to update the appropriate vblank counter * (specified by @crtc). Deal with wraparound, if it occurred, and * update the last read value so we can deal with wraparound on the next * call if necessary. * * Only necessary when going from off->on, to account for frames we * didn't get an interrupt for. * * Note: caller must hold dev->vbl_lock since this reads & writes * device vblank fields. */ static void drm_update_vblank_count(struct drm_device *dev, int crtc) { u32 cur_vblank, diff, tslot, rc; struct timeval t_vblank; /* * Interrupts were disabled prior to this call, so deal with counter * wrap if needed. * NOTE! It's possible we lost a full dev->max_vblank_count events * here if the register is small or we had vblank interrupts off for * a long time. * * We repeat the hardware vblank counter & timestamp query until * we get consistent results. This to prevent races between gpu * updating its hardware counter while we are retrieving the * corresponding vblank timestamp. */ do { cur_vblank = dev->driver->get_vblank_counter(dev, crtc); rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); /* Deal with counter wrap */ diff = cur_vblank - dev->vblank[crtc].last; if (cur_vblank < dev->vblank[crtc].last) { diff += dev->max_vblank_count; DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", crtc, dev->vblank[crtc].last, cur_vblank, diff); } DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", crtc, diff); /* Reinitialize corresponding vblank timestamp if high-precision query * available. Skip this step if query unsupported or failed. Will * reinitialize delayed at next vblank interrupt in that case. */ if (rc) { tslot = atomic_read(&dev->vblank[crtc].count) + diff; vblanktimestamp(dev, crtc, tslot) = t_vblank; } smp_mb__before_atomic(); atomic_add(diff, &dev->vblank[crtc].count); smp_mb__after_atomic(); } /** * drm_vblank_enable - enable the vblank interrupt on a CRTC * @dev: DRM device * @crtc: CRTC in question */ static int drm_vblank_enable(struct drm_device *dev, int crtc) { int ret = 0; assert_spin_locked(&dev->vbl_lock); spin_lock(&dev->vblank_time_lock); if (!dev->vblank[crtc].enabled) { /* * Enable vblank irqs under vblank_time_lock protection. * All vblank count & timestamp updates are held off * until we are done reinitializing master counter and * timestamps. Filtercode in drm_handle_vblank() will * prevent double-accounting of same vblank interval. */ ret = dev->driver->enable_vblank(dev, crtc); DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret); if (ret) atomic_dec(&dev->vblank[crtc].refcount); else { dev->vblank[crtc].enabled = true; drm_update_vblank_count(dev, crtc); } } spin_unlock(&dev->vblank_time_lock); return ret; } /** * drm_vblank_get - get a reference count on vblank events * @dev: DRM device * @crtc: which CRTC to own * * Acquire a reference count on vblank events to avoid having them disabled * while in use. * * This is the legacy version of drm_crtc_vblank_get(). * * Returns: * Zero on success, nonzero on failure. */ int drm_vblank_get(struct drm_device *dev, int crtc) { unsigned long irqflags; int ret = 0; if (WARN_ON(crtc >= dev->num_crtcs)) return -EINVAL; spin_lock_irqsave(&dev->vbl_lock, irqflags); /* Going from 0->1 means we have to enable interrupts again */ if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { ret = drm_vblank_enable(dev, crtc); } else { if (!dev->vblank[crtc].enabled) { atomic_dec(&dev->vblank[crtc].refcount); ret = -EINVAL; } } spin_unlock_irqrestore(&dev->vbl_lock, irqflags); return ret; } EXPORT_SYMBOL(drm_vblank_get); /** * drm_crtc_vblank_get - get a reference count on vblank events * @crtc: which CRTC to own * * Acquire a reference count on vblank events to avoid having them disabled * while in use. * * This is the native kms version of drm_vblank_off(). * * Returns: * Zero on success, nonzero on failure. */ int drm_crtc_vblank_get(struct drm_crtc *crtc) { return drm_vblank_get(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_get); /** * drm_vblank_put - give up ownership of vblank events * @dev: DRM device * @crtc: which counter to give up * * Release ownership of a given vblank counter, turning off interrupts * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. * * This is the legacy version of drm_crtc_vblank_put(). */ void drm_vblank_put(struct drm_device *dev, int crtc) { BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0); if (WARN_ON(crtc >= dev->num_crtcs)) return; /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&dev->vblank[crtc].refcount) && (drm_vblank_offdelay > 0)) mod_timer(&dev->vblank[crtc].disable_timer, jiffies + ((drm_vblank_offdelay * HZ)/1000)); } EXPORT_SYMBOL(drm_vblank_put); /** * drm_crtc_vblank_put - give up ownership of vblank events * @crtc: which counter to give up * * Release ownership of a given vblank counter, turning off interrupts * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. * * This is the native kms version of drm_vblank_put(). */ void drm_crtc_vblank_put(struct drm_crtc *crtc) { drm_vblank_put(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_put); /** * drm_vblank_off - disable vblank events on a CRTC * @dev: DRM device * @crtc: CRTC in question * * Drivers can use this function to shut down the vblank interrupt handling when * disabling a crtc. This function ensures that the latest vblank frame count is * stored so that drm_vblank_on() can restore it again. * * Drivers must use this function when the hardware vblank counter can get * reset, e.g. when suspending. * * This is the legacy version of drm_crtc_vblank_off(). */ void drm_vblank_off(struct drm_device *dev, int crtc) { struct drm_pending_vblank_event *e, *t; struct timeval now; unsigned long irqflags; unsigned int seq; if (WARN_ON(crtc >= dev->num_crtcs)) return; spin_lock_irqsave(&dev->vbl_lock, irqflags); vblank_disable_and_save(dev, crtc); wake_up(&dev->vblank[crtc].queue); /* Send any queued vblank events, lest the natives grow disquiet */ seq = drm_vblank_count_and_time(dev, crtc, &now); spin_lock(&dev->event_lock); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != crtc) continue; DRM_DEBUG("Sending premature vblank event on disable: \ wanted %d, current %d\n", e->event.sequence, seq); list_del(&e->base.link); drm_vblank_put(dev, e->pipe); send_vblank_event(dev, e, seq, &now); } spin_unlock(&dev->event_lock); spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } EXPORT_SYMBOL(drm_vblank_off); /** * drm_crtc_vblank_off - disable vblank events on a CRTC * @crtc: CRTC in question * * Drivers can use this function to shut down the vblank interrupt handling when * disabling a crtc. This function ensures that the latest vblank frame count is * stored so that drm_vblank_on can restore it again. * * Drivers must use this function when the hardware vblank counter can get * reset, e.g. when suspending. * * This is the native kms version of drm_vblank_off(). */ void drm_crtc_vblank_off(struct drm_crtc *crtc) { drm_vblank_off(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_off); /** * drm_vblank_on - enable vblank events on a CRTC * @dev: DRM device * @crtc: CRTC in question * * This functions restores the vblank interrupt state captured with * drm_vblank_off() again. Note that calls to drm_vblank_on() and * drm_vblank_off() can be unbalanced and so can also be unconditionaly called * in driver load code to reflect the current hardware state of the crtc. * * This is the legacy version of drm_crtc_vblank_on(). */ void drm_vblank_on(struct drm_device *dev, int crtc) { unsigned long irqflags; if (WARN_ON(crtc >= dev->num_crtcs)) return; spin_lock_irqsave(&dev->vbl_lock, irqflags); /* re-enable interrupts if there's are users left */ if (atomic_read(&dev->vblank[crtc].refcount) != 0) WARN_ON(drm_vblank_enable(dev, crtc)); spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } EXPORT_SYMBOL(drm_vblank_on); /** * drm_crtc_vblank_on - enable vblank events on a CRTC * @crtc: CRTC in question * * This functions restores the vblank interrupt state captured with * drm_vblank_off() again. Note that calls to drm_vblank_on() and * drm_vblank_off() can be unbalanced and so can also be unconditionaly called * in driver load code to reflect the current hardware state of the crtc. * * This is the native kms version of drm_vblank_on(). */ void drm_crtc_vblank_on(struct drm_crtc *crtc) { drm_vblank_on(crtc->dev, drm_crtc_index(crtc)); } EXPORT_SYMBOL(drm_crtc_vblank_on); /** * drm_vblank_pre_modeset - account for vblanks across mode sets * @dev: DRM device * @crtc: CRTC in question * * Account for vblank events across mode setting events, which will likely * reset the hardware frame counter. * * This is done by grabbing a temporary vblank reference to ensure that the * vblank interrupt keeps running across the modeset sequence. With this the * software-side vblank frame counting will ensure that there are no jumps or * discontinuities. * * Unfortunately this approach is racy and also doesn't work when the vblank * interrupt stops running, e.g. across system suspend resume. It is therefore * highly recommended that drivers use the newer drm_vblank_off() and * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when * using "cooked" software vblank frame counters and not relying on any hardware * counters. * * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc * again. */ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) { /* vblank is not initialized (IRQ not installed ?), or has been freed */ if (!dev->num_crtcs) return; if (WARN_ON(crtc >= dev->num_crtcs)) return; /* * To avoid all the problems that might happen if interrupts * were enabled/disabled around or between these calls, we just * have the kernel take a reference on the CRTC (just once though * to avoid corrupting the count if multiple, mismatch calls occur), * so that interrupts remain enabled in the interim. */ if (!dev->vblank[crtc].inmodeset) { dev->vblank[crtc].inmodeset = 0x1; if (drm_vblank_get(dev, crtc) == 0) dev->vblank[crtc].inmodeset |= 0x2; } } EXPORT_SYMBOL(drm_vblank_pre_modeset); /** * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes * @dev: DRM device * @crtc: CRTC in question * * This function again drops the temporary vblank reference acquired in * drm_vblank_pre_modeset. */ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) { unsigned long irqflags; /* vblank is not initialized (IRQ not installed ?), or has been freed */ if (!dev->num_crtcs) return; if (dev->vblank[crtc].inmodeset) { spin_lock_irqsave(&dev->vbl_lock, irqflags); dev->vblank_disable_allowed = true; spin_unlock_irqrestore(&dev->vbl_lock, irqflags); if (dev->vblank[crtc].inmodeset & 0x2) drm_vblank_put(dev, crtc); dev->vblank[crtc].inmodeset = 0; } } EXPORT_SYMBOL(drm_vblank_post_modeset); /* * drm_modeset_ctl - handle vblank event counter changes across mode switch * @DRM_IOCTL_ARGS: standard ioctl arguments * * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET * ioctls around modesetting so that any lost vblank events are accounted for. * * Generally the counter will reset across mode sets. If interrupts are * enabled around this call, we don't have to do anything since the counter * will have already been incremented. */ int drm_modeset_ctl(struct drm_device *dev, void *data, struct drm_file *file_priv) { struct drm_modeset_ctl *modeset = data; unsigned int crtc; /* If drm_vblank_init() hasn't been called yet, just no-op */ if (!dev->num_crtcs) return 0; /* KMS drivers handle this internally */ if (drm_core_check_feature(dev, DRIVER_MODESET)) return 0; crtc = modeset->crtc; if (crtc >= dev->num_crtcs) return -EINVAL; switch (modeset->cmd) { case _DRM_PRE_MODESET: drm_vblank_pre_modeset(dev, crtc); break; case _DRM_POST_MODESET: drm_vblank_post_modeset(dev, crtc); break; default: return -EINVAL; } return 0; } static int drm_queue_vblank_event(struct drm_device *dev, int pipe, union drm_wait_vblank *vblwait, struct drm_file *file_priv) { struct drm_pending_vblank_event *e; struct timeval now; unsigned long flags; unsigned int seq; int ret; e = kzalloc(sizeof *e, GFP_KERNEL); if (e == NULL) { ret = -ENOMEM; goto err_put; } e->pipe = pipe; e->base.pid = current->pid; e->event.base.type = DRM_EVENT_VBLANK; e->event.base.length = sizeof e->event; e->event.user_data = vblwait->request.signal; e->base.event = &e->event.base; e->base.file_priv = file_priv; e->base.destroy = (void (*) (struct drm_pending_event *)) kfree; spin_lock_irqsave(&dev->event_lock, flags); if (file_priv->event_space < sizeof e->event) { ret = -EBUSY; goto err_unlock; } file_priv->event_space -= sizeof e->event; seq = drm_vblank_count_and_time(dev, pipe, &now); if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && (seq - vblwait->request.sequence) <= (1 << 23)) { vblwait->request.sequence = seq + 1; vblwait->reply.sequence = vblwait->request.sequence; } DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n", vblwait->request.sequence, seq, pipe); trace_drm_vblank_event_queued(current->pid, pipe, vblwait->request.sequence); e->event.sequence = vblwait->request.sequence; if ((seq - vblwait->request.sequence) <= (1 << 23)) { drm_vblank_put(dev, pipe); send_vblank_event(dev, e, seq, &now); vblwait->reply.sequence = seq; } else { /* drm_handle_vblank_events will call drm_vblank_put */ list_add_tail(&e->base.link, &dev->vblank_event_list); vblwait->reply.sequence = vblwait->request.sequence; } spin_unlock_irqrestore(&dev->event_lock, flags); return 0; err_unlock: spin_unlock_irqrestore(&dev->event_lock, flags); kfree(e); err_put: drm_vblank_put(dev, pipe); return ret; } /* * Wait for VBLANK. * * \param inode device inode. * \param file_priv DRM file private. * \param cmd command. * \param data user argument, pointing to a drm_wait_vblank structure. * \return zero on success or a negative number on failure. * * This function enables the vblank interrupt on the pipe requested, then * sleeps waiting for the requested sequence number to occur, and drops * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that * after a timeout with no further vblank waits scheduled). */ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_priv) { union drm_wait_vblank *vblwait = data; int ret; unsigned int flags, seq, crtc, high_crtc; if (!dev->irq_enabled) return -EINVAL; if (vblwait->request.type & _DRM_VBLANK_SIGNAL) return -EINVAL; if (vblwait->request.type & ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | _DRM_VBLANK_HIGH_CRTC_MASK)) { DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n", vblwait->request.type, (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | _DRM_VBLANK_HIGH_CRTC_MASK)); return -EINVAL; } flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK); if (high_crtc) crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT; else crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; if (crtc >= dev->num_crtcs) return -EINVAL; ret = drm_vblank_get(dev, crtc); if (ret) { DRM_DEBUG("failed to acquire vblank counter, %d\n", ret); return ret; } seq = drm_vblank_count(dev, crtc); switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { case _DRM_VBLANK_RELATIVE: vblwait->request.sequence += seq; vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; case _DRM_VBLANK_ABSOLUTE: break; default: ret = -EINVAL; goto done; } if (flags & _DRM_VBLANK_EVENT) { /* must hold on to the vblank ref until the event fires * drm_vblank_put will be called asynchronously */ return drm_queue_vblank_event(dev, crtc, vblwait, file_priv); } if ((flags & _DRM_VBLANK_NEXTONMISS) && (seq - vblwait->request.sequence) <= (1<<23)) { vblwait->request.sequence = seq + 1; } DRM_DEBUG("waiting on vblank count %d, crtc %d\n", vblwait->request.sequence, crtc); dev->vblank[crtc].last_wait = vblwait->request.sequence; DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ, (((drm_vblank_count(dev, crtc) - vblwait->request.sequence) <= (1 << 23)) || !dev->vblank[crtc].enabled || !dev->irq_enabled)); if (ret != -EINTR) { struct timeval now; vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now); vblwait->reply.tval_sec = now.tv_sec; vblwait->reply.tval_usec = now.tv_usec; DRM_DEBUG("returning %d to client\n", vblwait->reply.sequence); } else { DRM_DEBUG("vblank wait interrupted by signal\n"); } done: drm_vblank_put(dev, crtc); return ret; } static void drm_handle_vblank_events(struct drm_device *dev, int crtc) { struct drm_pending_vblank_event *e, *t; struct timeval now; unsigned long flags; unsigned int seq; seq = drm_vblank_count_and_time(dev, crtc, &now); spin_lock_irqsave(&dev->event_lock, flags); list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { if (e->pipe != crtc) continue; if ((seq - e->event.sequence) > (1<<23)) continue; DRM_DEBUG("vblank event on %d, current %d\n", e->event.sequence, seq); list_del(&e->base.link); drm_vblank_put(dev, e->pipe); send_vblank_event(dev, e, seq, &now); } spin_unlock_irqrestore(&dev->event_lock, flags); trace_drm_vblank_event(crtc, seq); } /** * drm_handle_vblank - handle a vblank event * @dev: DRM device * @crtc: where this event occurred * * Drivers should call this routine in their vblank interrupt handlers to * update the vblank counter and send any signals that may be pending. */ bool drm_handle_vblank(struct drm_device *dev, int crtc) { u32 vblcount; s64 diff_ns; struct timeval tvblank; unsigned long irqflags; if (!dev->num_crtcs) return false; if (WARN_ON(crtc >= dev->num_crtcs)) return false; /* Need timestamp lock to prevent concurrent execution with * vblank enable/disable, as this would cause inconsistent * or corrupted timestamps and vblank counts. */ spin_lock_irqsave(&dev->vblank_time_lock, irqflags); /* Vblank irq handling disabled. Nothing to do. */ if (!dev->vblank[crtc].enabled) { spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); return false; } /* Fetch corresponding timestamp for this vblank interval from * driver and store it in proper slot of timestamp ringbuffer. */ /* Get current timestamp and count. */ vblcount = atomic_read(&dev->vblank[crtc].count); drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); /* Compute time difference to timestamp of last vblank */ diff_ns = timeval_to_ns(&tvblank) - timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); /* Update vblank timestamp and count if at least * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds * difference between last stored timestamp and current * timestamp. A smaller difference means basically * identical timestamps. Happens if this vblank has * been already processed and this is a redundant call, * e.g., due to spurious vblank interrupts. We need to * ignore those for accounting. */ if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { /* Store new timestamp in ringbuffer. */ vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; /* Increment cooked vblank count. This also atomically commits * the timestamp computed above. */ smp_mb__before_atomic(); atomic_inc(&dev->vblank[crtc].count); smp_mb__after_atomic(); } else { DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", crtc, (int) diff_ns); } wake_up(&dev->vblank[crtc].queue); drm_handle_vblank_events(dev, crtc); spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); return true; } EXPORT_SYMBOL(drm_handle_vblank);