drm/i915/bxt: backlight clock gating workaround

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Per bspec, "Backlight PWM may stop in the asserted state, causing
backlight to stay fully on. WA: Before disabling PWM, set CLKGATE_DIS_0
0x46530 bit 13 PWM1 Gating Dis (for PWM1) or bit 14 PWM2 Gating Dis (for
PWM2). The bits can remain set without harm." (There's no workaround
name for this.)

This fixes some Broxton backlight issues.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[Jani: cleanup & commit message]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448958232-26520-3-git-send-email-jani.nikula@intel.com

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Imre Deak 2015-12-01 10:23:52 +02:00 • committed by Jani Nikula

parent 5075222b04

commit d965e7ac7a

2 changed files with 15 additions and 0 deletions

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7

drivers/gpu/drm/i915/i915_reg.h

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8

drivers/gpu/drm/i915/intel_pm.c

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