From 7f1241ed1a06b4846ad7a2a57eb088b757e58e16 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 18 Dec 2014 11:44:06 +0200 Subject: [PATCH] drm/i915: Kill check_power_well() calls MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 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: stable@vger.kernel.org (v3.18+) Cc: Egbert Eich Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86201 Tested-by: Wendy Wang Signed-off-by: Ville Syrjälä Signed-off-by: Jani Nikula --- Reading git-format-patch failed