ARRAY_SIZE is number of elements not bytes. Fix
ring counts accordingly, also make a few functions
static.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
When an output was disconnected, its mode list would remain. If you later
plugged into a sink with no EDID (projector, etc), you'd inherit the mode
list from the old sink, which is not what you want.
taken from Fedora kernel
Signed-off-by: Dave Airlie <airlied@redhat.com>
The driver gets the bridge device in a number of places, upcoming
vga arb code paths need the bridge device, however they need it in
under a lock, and the pci lookup can allocate memory. So clean
this code up before then and get the bridge once for the driver lifetime.
Signed-off-by: Dave Airlie <airlied@redhat.com>
This adds the r600 KMS + CS support to the Linux kernel.
The r600 TTM support is quite basic and still needs more
work esp around using interrupts, but the polled fencing
should work okay for now.
Also currently TTM is using memcpy to do VRAM moves,
the code is here to use a 3D blit to do this, but
isn't fully debugged yet.
Authors:
Alex Deucher <alexdeucher@gmail.com>
Dave Airlie <airlied@redhat.com>
Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This ports the tv-out code from the DDX to KMS.
adds a radeon.tv module option, radeon.tv=0 to disable tv
Signed-off-by: Dave Airlie <airlied@redhat.com>
This adds the command stream checker for the RN50, R100 and R200 cards.
It stops any access to 3D registers on RN50, and does checks
on buffer sizes on the r100/r200 cards. It also fixes some texture
sizing checks on r300.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The new code adds modes in the helper, which makes more sense
I disliked the non-driver code adding modes.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add the default mode for every output device when there
is no mode for it.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Add a function that can be used to add the default mode for the output device
without EDID.
It will add the default mode that meets with the requirements of given
hdisplay/vdisplay limit.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
When we need to add the standard timing mode, we will firstly check whether it
can be found in DMT table by comparing the hdisplay/vdisplay/vfresh_rate.
If it can't be found, then we will use the cvt/gtf to add the required mode.
If it can be found, it will be returned.
At the same time the function of drm_mode_vrefresh is also fixed. It will
return the result of actual refresh_rate plus 0.5.
For example:
When the calculated value is 84.9, then the fresh_rate is 85.
When the calculated value is 70.02, then the fresh_rate is 70.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
When we add a standard timing mode in UMS, we will first check whether it can
be found in default mode table. If it can't be found, then we will use cvt/gtf
to add the standard timing mode.
Add the default mode table so that we can check whether the given mode
can be found in the default mode table as what we have done in UMS mode.
If the status of one output device is connected but there is no EDID, it will
have no correct mode. In such case we can add some default modes for it. Of
course we only add the modes in the default modes list that visible part is not
greater than 1024x768.
The default mode is autogenerated from the DMT spec. And it is copied from
xserver/hw/xfree86/modes/xf86EdidModes.c. But the mode with reduced blank
feature is removed.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
According to the docs, the ringbuffer is not allowed to wrap in the middle
of an instruction.
G45 PRM, Vol 1b, p101:
While the “free space” wrap may allow commands to be wrapped around the
end of the Ring Buffer, the wrap should only occur between commands.
Padding (with NOP) may be required to follow this restriction.
Do as commanded.
[Having seen bug reports where there is evidence of split commands, but
apparently the GPU has continued on merrily before a bizarre and untimely
death, this may or may not fix a few random hangs.]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
CC: Eric Anholt <eric@anholt.net>
Signed-off-by: Eric Anholt <eric@anholt.net>
mac Mini's have a single DDC line on the DVI connector, shared between the
analog link and the digital link. So, if DDC isn't detected on GPIOE (the
usual SDVO DDC link), try GPIOA (the usual VGA DDC link) when there isn't a
VGA monitor connected.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
It seems that on IGDNG the same swizzling setup always applys.
And front buffer tiling needs to set address swizzle in display
arb control too.
Fix plane tricle feed setting in v1 which should be disable bit,
and always setup address swizzle to let hardware care for buffer
tiling in all cases.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
And clean up a small whitespace goof-up in the same function, while
I was looking at it.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Eric Anholt <eric@anholt.net>
There are several sources of unnecessary power consumption on Intel
graphics systems. The first is the LVDS clock. TFTs don't suffer from
persistence issues like CRTs, and so we can reduce the LVDS refresh rate
when the screen is idle. It will be automatically upclocked when
userspace triggers graphical activity. Beyond that, we can enable memory
self refresh. This allows the memory to go into a lower power state when
the graphics are idle. Finally, we can drop some clocks on the gpu
itself. All of these things can be reenabled between frames when GPU
activity is triggered, and so there should be no user visible graphical
changes.
Signed-off-by: Jesse Barnes <jesse.barnes@intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
In the event that any one of the DAC analog outputs (R,G,B) were driven
at full-scale (white video) or some analog level close to full-scale
voltage, and if the video cable were then disconnected, the analog video
voltage level would exceed the maximum electrical overstress limit of the
native (thin-oxide) transistors thus causing a long-term reliability concern.
The electrical overstress condition occurs in this particular case.
This patch address the IGD EOS (electrical overstress condition) issue.
When the EOS interrupt occurs, OS should disable DAC and then disable EOS,
then the normal hotplug operation follows.
TODO: it appears the normal unplug interrupt is missed as reported by Li Peng,
need more checks here.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Currently SDVO TV only support NTSC-M format. In this patch
we introduce PAL and SECAM formats available and create seting-format
property at init time. When user dynamically chose preferred
format by xrandr command, it will refine all modelines
provided by SDVO device, then instruct SDVO device to execute.
At the same time the property is added for SDVO-TV so that the SDVO-TV mode can be changed
by using xrandr.
https://bugs.freedesktop.org/show_bug.cgi?id=22891
Signed-off-by: Ma Ling <ling.ma@intel.com>
review-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
For integrated TV there are 3 connector types: S-VIDEO, Composite and
Component(YprPb). Those tv formats whose component flag is true should
be assigned to Component connector, others are for S-VIDEO and Composite.
The patch intends to find appropriate tv format for each connector.
In such case it will return the correct modeline to user space. Otherwise
it will return the incorrect modeline when S-video/composite is connected.
Signed-off-by: Ma Ling <ling.ma@intel.com>
reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Add a debugfs file to dump the entire register range. Here we
assume that reading write-only/reserved registers won't make the chip
angry. Seems to hold true, thankfully.
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Remember to release the local reference if we fail to wait on
the rendering.
(Also whilst in the vicinity add some whitespace so that the phasing of
the operations is clearer.)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
Some i915/i945 platforms have a fairly high memory latency in certain
situations, so increase our constant a bit to avoid FIFO underruns.
The effect should be positive on other platforms as well; we'll have a
bit more insurance against a busy memory subsystem due to the extra
FIFO entries.
Fixes fdo bug #23368. Needed for 2.6.31.
Tested-by: Sven Arvidsson <sa@whiz.se>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
For shared tv-out and VGA encoders, we really need to know if
the encoder is just being switched off temporarily in blanking
or if we are really disabling it hard.
Also we need to try harder to disconnect encoders from unused
connectors so we can share more efficently.
(shared encoders stuff is coming in radeon tv-out support)
Signed-off-by: Dave Airlie <airlied@redhat.com>
This produces a warn on for architectures where this gets called
but we don't have a cache flushing implementation suitable.
Signed-off-by: Dave Airlie <airlied@redhat.com>
This adds code to the drm_mm to talk to debugfs, and adds
support to radeon to add the VRAM and GTT mm lists to debugfs.
I tested with spinlock debugging and it doesn't give out.
Signed-off-by: Dave Airlie <airlied@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
drm/i915: Improve CRTDDC mapping by using VBT info
drm/i915: Fix CPU-spinning hangs related to fence usage by using an LRU.
drm/i915: Set crtc/clone mask in different output devices
drm/i915: Always use SDVO_B detect bit for SDVO output detection.
drm/i915: Fix typo that broke SVID1 in intel_sdvo_multifunc_encoder()
drm/i915: Check if BIOS enabled dual-channel LVDS on 8xx, not only on 9xx
drm/i915: Set the multiplier for SDVO on G33 platform
Set accel to none, we really don't want anyone thinking
fb is an accel interface.
Pass pitch not depth to function for intel.
Signed-off-by: Dave Airlie <airlied@redhat.com>
airlied: fixup race against drm info by filling out
tmp before adding it to proc.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Sometimes we can obtain the EDID with multiple blocks from the display device.
For example: HDMI monitor.
When the CEA-EDID block is detected, we should also parse the detailed timing
info from it. Otherwise we will lose some modes for the display device.
The first step is check whether the CEA EDID block is found. If it exists,
it will skip the CEA-data block and parse the detailed timing info.
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Initially I always meant this code to be shared, but things
ran away from me before I got to it.
This refactors the i915 and radeon kms fbdev interaction layers
out into generic helpers + driver specific pieces.
It moves all the panic/sysrq enhancements to the core file,
and stores a linked list of kernel fbs. This could possibly be
improved to only store the fb which has fbcon on it for panics
etc.
radeon retains some specific codes used for a big endian
workaround.
changes:
fix oops in v1
fix freeing path for crtc_info
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Almost all r128's private ioctls require that the CCE state has
already been initialised. However, most do not test that this has
been done, and will proceed to dereference a null pointer. This may
result in a security vulnerability, since some ioctls are
unprivileged.
This adds a macro for the common initialisation test and changes all
ioctl implementations that require prior initialisation to use that
macro.
Also, r128_do_init_cce() does not test that the CCE state has not
been initialised already. Repeated initialisation may lead to a crash
or resource leak. This adds that test.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Loosely based on a patch by
Jaswinder Singh Rajput <jaswinderlinux@gmail.com>.
KMS support by Dave Airlie <airlied@redhat.com>.
For Radeon 100- to 500-series, firmware blobs look like:
struct {
__be32 datah;
__be32 datal;
} cp_ucode[256];
For Radeon 600-series, there are two separate firmware blobs:
__be32 me_ucode[PM4_UCODE_SIZE * 3];
__be32 pfp_ucode[PFP_UCODE_SIZE];
For Radeon 700-series, likewise:
__be32 me_ucode[R700_PM4_UCODE_SIZE];
__be32 pfp_ucode[R700_PFP_UCODE_SIZE];
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
- Previously the old encoder would be called during modeset and without a connector bad things happened.
Signed-off-by: Maarten Maathuis <madman2003@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
- The previous system was not very transparent, nor flexible.
- This is needed to be able to fix a few bugs in the mechanism.
Signed-off-by: Maarten Maathuis <madman2003@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Use VBT information to determine which DDC bus to use for CRTDCC.
Fall back to GPIOA if VBT info is not available.
Signed-off-by: David Müller <d.mueller@elsoft.ch>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Tested on: 855 (David), and 945GM, 965GM, GM45, and G45 (anholt)
Several functions in the GEM kernel API used int as handle type, but
user API has it __u32 which is also the intended type.
Replace int with u32.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Image format is IHEX, one record for each pipe in order (record
addresses are ignored).
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Based on Bspec each encoder has different sharing pipe property,
i.e. Integrated or SDVO TV both will occupy one pipe exclusively,
and sdvo-non-tv and crt are allowed to share one. The patch moves
sharing judgment into differnet output functions, and sets the right
clone bit.
This fixes both HDMI outputs choosing the same pipe.
https://bugs.freedesktop.org/show_bug.cgi?id=22247
Signed-off-by: Ma Ling <ling.ma@intel.com>
Reviewed-by : Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
After the following commit is shipped, the SDVO C detection will depend on
the SDVO_C/DP detion bit.
commit 13520b051e
Author: Kristian Høgsberg <krh@redhat.com>
Date: Fri Mar 13 15:42:14 2009 -0400
drm/i915: Read the right SDVO register when detecting SVDO/HDMI.
According to the spec we should continue to detect the SDVO_B/C based on
the SDVO_B detection bit. The new detection bit on G4X platform is for
the HDMI_C detection rather than SDVO_C detection.
https://bugs.freedesktop.org/show_bug.cgi?id=20639
Signed-off-by: Ma Ling <ling.ma@intel.com>
Acked-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Commit 0c2e39525b is not sufficient to
get fd.o bug #20115 fixed.
In addition intel_find_best_PLL() must not only rely on BIOS settings
for i9xx chips but also for i8xx, so drop the IS_I9XX() check.
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
http://bugs.freedesktop.org/show_bug.cgi?id=21417
Signed-off-by: Sean Young <sean@mess.org>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Previously we just made these offline and included them,
but no reason we can't generate them at build time.
TODO: add rs690 + r100/r200 when done.
should we do rs480/rs690 no tcl version?
Signed-off-by: Dave Airlie <airlied@redhat.com>
The drm sysfs class suspend / resume methods could not distinguish
between different device types wich could lead to illegal type casts.
Use struct device_type and make sure the class suspend / resume callbacks
are aware of those. There is no per device-type suspend / resume. Only
new-style PM.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The previous patch assumes the ioctl already existed, when
it actually didn't.
It also didn't return the correct error code.
Signed-off-by: Dave Airlie <airlied@redhat.com>
ttm:
Fix error paths when kobject_add returns an error.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
ttm:
Remove a stray debug printout.
Remove a re-init of the lru spinlock at device init.
radeon:
Fix the size of the bo_global allocation.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Common resources, like memory accounting and swap lists should be
global and not per device. Introduce a struct ttm_bo_global to
accomodate this, and register it with sysfs. Add a small sysfs interface
to return the number of active buffer objects.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Use inclusive zones to simplify accounting and its sysfs representation.
Use DMA32 accounting where applicable.
Add a sysfs interface to make the heuristically determined limits
readable and configurable.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
The device directory will be the base directory of the
sysfs representation of other ttm subsystems.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Export utility functions for drivers to add specialized devices in the
sysfs drm class subdirectory.
Initially this will be needed form TTM to add a virtual device that
handles power management.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Now that we're using the scaling property in the Intel driver I noticed
that the names were a bit confusing. I've corrected them according to
our discussion on IRC and the mailing list, though I've left out
potential new additions for a new scaling property with an integer (or
two) for the scaling factor. None of the drivers implement that today,
but if someone wants to do it, I think it could be done with the
addition of a single new type and a new property to describe the
scaling factor in the X and Y directions.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Just a DRM_MASTER flag is sufficient here, though maybe this call is
totally deprecated anyway (xf86-video-intel still calls it though).
(airlied: drop ioctl auth_magic as discussed on mailing list also)
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
If userspace destroys a framebuffer that is in use on a crtc,
don't just null it out, tear down the crtc properly so the
hw gets turned off.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The fallback case wasn't getting executed properly if there
was no TV table, which my T42 M7 hasn't got.
Signed-off-by: Dave Airlie <airlied@redhat.com>
LVDS always requests RMX_FULL, we need to fix it so that doesn't happen
before we can enable LVDS on crtc 1.
Signed-off-by: Dave Airlie <airlied@redhat.com>
This implements the busy ioctl along with a current domain check.
returns 0 or -EBUSY
puts the current domain no matter what the answer.
Signed-off-by: Dave Airlie <airlied@redhat.com>
We really don't want to be doing all these indirects, updating
the GPU gart table is something we do often so the less overhead the
better.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Fixes 3D apps timing out in the WAIT_VBLANK ioctl.
AVIVO bits compile-tested only.
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
this syncs the versioning check with the code the X server uses.
Reported-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Dave Airlie <airlied@redhat.com>
rs690 is r3xx 3D engine with AVIVO modesetting so we need to allow
AVIVO register for vline synchronization. This add a specific table
to rs690 to handle that. Thanks to Marc (marvin24) for debugging
this and kudos to Andre (taiu1) for spotting the origin of the bugs.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Overscan, saturation, hue. Used in the nouveau driver for GPUs with
integrated TV encoders.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The calculated vdisplay was half the right value.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Some applications/hardware combinations are triggering the message "failed to
acquire vblank counter" to be issued up to 20 times a second, which makes it
both useless and dangerous, as this may hide other important messages.
This changes makes it only appear when people are debugging.
Signed-off-by: Paul Rolland <rol@as2917.net>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Lost-twice-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The code which takes probed modes and adds them to a connector eliminates
duplicate modes by comparing them using drm_mode_equal. That function
doesn't consider the type bits, which means that any modes which differ only
in the type field will be lost.
One of the bits in the mode->type field is the DRM_MODE_TYPE_PREFERRED bit.
If the mode with that bit is lost, then higher level code will not know
which mode to select, causing a random mode to be used instead.
This patch simply merges the two mode type bits together; that seems
reasonable to me, but perhaps only a subset of the bits should be used? None
of these can be user defined as they all come from looking at just the
hardware.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel: (22 commits)
drm/i915: Fix read outside array bounds in restoring the SWF10 range.
drm/i915: Use our own workqueue to avoid wedging the system along with the GPU.
drm/i915: Add support for dual-channel LVDS on 8xx.
drm/i915: Return disconnected for SDVO DVI when there's no digital EDID.
drm/i915: Choose real sdvo output according to result from detection
drm/i915: Set preferred mode for integrated TV according to TV format
drm/i915: fix 845G FIFO size & burst length
drm/i915: fix VGA detect on IGDNG
drm/i915: Add eDP support on IGDNG mobile chip
drm/i915: enable DisplayPort support on IGDNG
drm/i915: Fix channel ending action for DP aux transaction
drm/i915: fix issue in display pipe setup on IGDNG
drm/i915: disable VGA plane reliably
drm/I915: Fix offset to DVO timings in LVDS data
drm/i915: hdmi detection according by reading edid
drm/i915: correct self-refresh calculation in "everything off" case
drm/i915: handle FIFO oversubsription correctly
drm/i915: FIFO watermark calculation fixes
drm/i915: ignore lvds on AOpen Mini PC MP-915
drm/i915: Allow frame buffers up to 4096x4096 on 915/945 class hardware
...