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| author | Shawn Lee <shawn.c.lee@intel.com> | 2016-09-19 13:35:26 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2016-10-10 16:05:52 +0300 |
| commit | 915b417946030e1f365c63728875cffd8db8e880 (patch) | |
| tree | 116201b97ab343d41f27a07c7c8c8230d15f24d3 /drivers/gpu | |
| parent | 16e1203db8ab740c912ea62761fdf27d7811b886 (diff) | |
| download | linux-915b417946030e1f365c63728875cffd8db8e880.tar.gz linux-915b417946030e1f365c63728875cffd8db8e880.tar.bz2 linux-915b417946030e1f365c63728875cffd8db8e880.zip | |
drm/i915/backlight: setup backlight pwm alternate increment on backlight enable
Backlight enable is supposed to do a full setup of the backlight. We
were missing the PWM alternate increment bit in the south chicken
registers on lpt+ pch. This potentially caused a PWM frequency change
when the chicken register value was lost e.g. on suspend.
v2 by Jani, rebase on the patch caching alt increment
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97486
References: https://bugs.freedesktop.org/show_bug.cgi?id=67454
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: Wei Shun Chen <wei.shun.chang@intel.com>
Cc: Gary C Wang <gary.c.wang@intel.com>
Cc: stable@vger.kernel.org # v4.4+ 16e1203db8ab drm/i915/backlight: setup and cache...
Cc: stable@vger.kernel.org # v4.4+
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shawn Lee <shawn.c.lee@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/8265f5935bd31c039ddfc82819d26c2ca1ae9cba.1474281249.git.jani.nikula@intel.com
(cherry picked from commit e29aff05f239f8dd24e9ee7816fd96726e20105a)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_panel.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 8bc43205d6a0..be4b4d546fd9 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -841,7 +841,7 @@ static void lpt_enable_backlight(struct intel_connector *connector) { struct drm_i915_private *dev_priv = to_i915(connector->base.dev); struct intel_panel *panel = &connector->panel; - u32 pch_ctl1, pch_ctl2; + u32 pch_ctl1, pch_ctl2, schicken; pch_ctl1 = I915_READ(BLC_PWM_PCH_CTL1); if (pch_ctl1 & BLM_PCH_PWM_ENABLE) { @@ -850,6 +850,22 @@ static void lpt_enable_backlight(struct intel_connector *connector) I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1); } + if (HAS_PCH_LPT(dev_priv)) { + schicken = I915_READ(SOUTH_CHICKEN2); + if (panel->backlight.alternate_pwm_increment) + schicken |= LPT_PWM_GRANULARITY; + else + schicken &= ~LPT_PWM_GRANULARITY; + I915_WRITE(SOUTH_CHICKEN2, schicken); + } else { + schicken = I915_READ(SOUTH_CHICKEN1); + if (panel->backlight.alternate_pwm_increment) + schicken |= SPT_PWM_GRANULARITY; + else + schicken &= ~SPT_PWM_GRANULARITY; + I915_WRITE(SOUTH_CHICKEN1, schicken); + } + pch_ctl2 = panel->backlight.max << 16; I915_WRITE(BLC_PWM_PCH_CTL2, pch_ctl2); |