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authorVille Syrjälä <ville.syrjala@linux.intel.com>2014-12-18 11:44:06 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-27 08:29:46 -0800
commit3e038e9d2df3167f234ff7b5730642319d590e99 (patch)
treec311a7836ecaeaf10a071a33441f84aaf4f4aadd /Documentation/acpi
parent65f81ccbd1e33872b1b47bc550e452e7e3dadf58 (diff)
drm/i915: Kill check_power_well() calls
commit 7f1241ed1a06b4846ad7a2a57eb088b757e58e16 upstream. pps_{lock,unlock}() call intel_display_power_{get,put}() outside pps_mutes to avoid deadlocks with the power_domain mutex. In theory during aux transfers we should usually have the relevant power domain references already held by some higher level code, so this should not result in much overhead (exception being userspace i2c-dev access). However thanks to the check_power_well() calls in intel_display_power_{get/put}() we end up doing a few Punit reads for each aux transfer. Obviously doing this for each byte transferred via i2c-over-aux is not a good idea. I can't think of a good way to keep check_power_well() while eliminating the overhead, so let's just remove check_power_well() entirely. Fixes a driver init time regression introduced by: commit 773538e86081d146e0020435d614f4b96996c1f9 Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Thu Sep 4 14:54:56 2014 +0300 drm/i915: Reset power sequencer pipe tracking when disp2d is off Credit goes to Jani for figuring this out. v2: Add the regression note in the commit message. Cc: Egbert Eich <eich@suse.de> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86201 Tested-by: Wendy Wang <wendy.wang@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> [Jani: s/intel_runtime_pm.c/intel_pm.c/g and wiggle for 3.18] Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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