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drm/i915: Fix blank panel at reopening lid 

When you reopen the lid on a laptop with PCH, the panel suddenly goes
blank sometimes.  It seems because BLC_PWM_CPU_CTL register is cleared
to zero when BLC_PWM_CPU_CTL2 and BLC_PWM_PCH_CTL1 registers are
enabled.

This patch fixes the problem by moving the call of the function setting
BLC_PWM_CPU_CTL after enabling other two registers.

Reported-and-tested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Takashi Iwai 2012-08-11 08:56:42 +02:00 committed by Daniel Vetter
parent 9830605d4c
commit 770c12312a
1 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/gpu/drm/i915/intel_panel.c
View File

@ -311,9 +311,6 @@ void intel_panel_enable_backlight(struct drm_device *dev,
if (dev_priv->backlight_level == 0)
dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
dev_priv->backlight_enabled = true;
intel_panel_actually_set_backlight(dev, dev_priv->backlight_level);
if (INTEL_INFO(dev)->gen >= 4) {
uint32_t reg, tmp;
@ -326,7 +323,7 @@ void intel_panel_enable_backlight(struct drm_device *dev,
* we don't track the backlight dpms state, hence check whether
* we have to do anything first. */
if (tmp & BLM_PWM_ENABLE)
return;
goto set_level;
if (dev_priv->num_pipe == 3)
tmp &= ~BLM_PIPE_SELECT_IVB;
@ -347,6 +344,14 @@ void intel_panel_enable_backlight(struct drm_device *dev,
I915_WRITE(BLC_PWM_PCH_CTL1, tmp);
}
}
set_level:
/* Call below after setting BLC_PWM_CPU_CTL2 and BLC_PWM_PCH_CTL1.
* BLC_PWM_CPU_CTL may be cleared to zero automatically when these
* registers are set.
*/
dev_priv->backlight_enabled = true;
intel_panel_actually_set_backlight(dev, dev_priv->backlight_level);
}
static void intel_panel_init_backlight(struct drm_device *dev)