drm/i915: Skip modifying PCH DREF if not changing clock sources

Modifying the clock sources (via the DREF control on the PCH) is a slow
multi-stage process as we need to let the clocks stabilise between each
stage. If we are not actually changing the clock sources, then we can
return early.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Appease checkpatch by deleting a space after a ~]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Chris Wilson 2013-03-26 16:33:04 -07:00 коммит произвёл Daniel Vetter
Родитель 31ad8ec6a6
Коммит 74cfd7ac5e
1 изменённых файлов: 62 добавлений и 23 удалений

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@ -4701,7 +4701,7 @@ static void ironlake_init_pch_refclk(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_mode_config *mode_config = &dev->mode_config;
struct intel_encoder *encoder;
u32 temp;
u32 val, final;
bool has_lvds = false;
bool has_cpu_edp = false;
bool has_pch_edp = false;
@ -4744,70 +4744,109 @@ static void ironlake_init_pch_refclk(struct drm_device *dev)
* PCH B stepping, previous chipset stepping should be
* ignoring this setting.
*/
temp = I915_READ(PCH_DREF_CONTROL);
/* Always enable nonspread source */
temp &= ~DREF_NONSPREAD_SOURCE_MASK;
val = I915_READ(PCH_DREF_CONTROL);
/* As we must carefully and slowly disable/enable each source in turn,
* compute the final state we want first and check if we need to
* make any changes at all.
*/
final = val;
final &= ~DREF_NONSPREAD_SOURCE_MASK;
if (has_ck505)
temp |= DREF_NONSPREAD_CK505_ENABLE;
final |= DREF_NONSPREAD_CK505_ENABLE;
else
temp |= DREF_NONSPREAD_SOURCE_ENABLE;
final |= DREF_NONSPREAD_SOURCE_ENABLE;
final &= ~DREF_SSC_SOURCE_MASK;
final &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
final &= ~DREF_SSC1_ENABLE;
if (has_panel) {
temp &= ~DREF_SSC_SOURCE_MASK;
temp |= DREF_SSC_SOURCE_ENABLE;
final |= DREF_SSC_SOURCE_ENABLE;
if (intel_panel_use_ssc(dev_priv) && can_ssc)
final |= DREF_SSC1_ENABLE;
if (has_cpu_edp) {
if (intel_panel_use_ssc(dev_priv) && can_ssc)
final |= DREF_CPU_SOURCE_OUTPUT_DOWNSPREAD;
else
final |= DREF_CPU_SOURCE_OUTPUT_NONSPREAD;
} else
final |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
} else {
final |= DREF_SSC_SOURCE_DISABLE;
final |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
}
if (final == val)
return;
/* Always enable nonspread source */
val &= ~DREF_NONSPREAD_SOURCE_MASK;
if (has_ck505)
val |= DREF_NONSPREAD_CK505_ENABLE;
else
val |= DREF_NONSPREAD_SOURCE_ENABLE;
if (has_panel) {
val &= ~DREF_SSC_SOURCE_MASK;
val |= DREF_SSC_SOURCE_ENABLE;
/* SSC must be turned on before enabling the CPU output */
if (intel_panel_use_ssc(dev_priv) && can_ssc) {
DRM_DEBUG_KMS("Using SSC on panel\n");
temp |= DREF_SSC1_ENABLE;
val |= DREF_SSC1_ENABLE;
} else
temp &= ~DREF_SSC1_ENABLE;
val &= ~DREF_SSC1_ENABLE;
/* Get SSC going before enabling the outputs */
I915_WRITE(PCH_DREF_CONTROL, temp);
I915_WRITE(PCH_DREF_CONTROL, val);
POSTING_READ(PCH_DREF_CONTROL);
udelay(200);
temp &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
val &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
/* Enable CPU source on CPU attached eDP */
if (has_cpu_edp) {
if (intel_panel_use_ssc(dev_priv) && can_ssc) {
DRM_DEBUG_KMS("Using SSC on eDP\n");
temp |= DREF_CPU_SOURCE_OUTPUT_DOWNSPREAD;
val |= DREF_CPU_SOURCE_OUTPUT_DOWNSPREAD;
}
else
temp |= DREF_CPU_SOURCE_OUTPUT_NONSPREAD;
val |= DREF_CPU_SOURCE_OUTPUT_NONSPREAD;
} else
temp |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
val |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
I915_WRITE(PCH_DREF_CONTROL, temp);
I915_WRITE(PCH_DREF_CONTROL, val);
POSTING_READ(PCH_DREF_CONTROL);
udelay(200);
} else {
DRM_DEBUG_KMS("Disabling SSC entirely\n");
temp &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
val &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
/* Turn off CPU output */
temp |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
val |= DREF_CPU_SOURCE_OUTPUT_DISABLE;
I915_WRITE(PCH_DREF_CONTROL, temp);
I915_WRITE(PCH_DREF_CONTROL, val);
POSTING_READ(PCH_DREF_CONTROL);
udelay(200);
/* Turn off the SSC source */
temp &= ~DREF_SSC_SOURCE_MASK;
temp |= DREF_SSC_SOURCE_DISABLE;
val &= ~DREF_SSC_SOURCE_MASK;
val |= DREF_SSC_SOURCE_DISABLE;
/* Turn off SSC1 */
temp &= ~ DREF_SSC1_ENABLE;
val &= ~DREF_SSC1_ENABLE;
I915_WRITE(PCH_DREF_CONTROL, temp);
I915_WRITE(PCH_DREF_CONTROL, val);
POSTING_READ(PCH_DREF_CONTROL);
udelay(200);
}
BUG_ON(val != final);
}
/* Sequence to enable CLKOUT_DP for FDI usage and configure PCH FDI I/O. */