From: Eugeni Dodonov Date: Thu, 5 Jan 2012 11:34:28 +0000 (-0200) Subject: drm: give up on edid retries when i2c bus is not responding X-Git-Tag: v3.2.36~165 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=da964048c0f36fb219a77f44335375eeb2b7c383;p=pandora-kernel.git drm: give up on edid retries when i2c bus is not responding commit 9292f37e1f5c79400254dca46f83313488093825 upstream. This allows to avoid talking to a non-responding bus repeatedly until we finally timeout after 15 attempts. We can do this by catching the -ENXIO error, provided by i2c_algo_bit:bit_doAddress call. Within the bit_doAddress we already try 3 times to get the edid data, so if the routine tells us that bus is not responding, it is mostly pointless to keep re-trying those attempts over and over again until we reach final number of retries. This change should fix https://bugs.freedesktop.org/show_bug.cgi?id=41059 and improve overall edid detection timing by 10-30% in most cases, and by a much larger margin in case of phantom outputs (up to 30x in one worst case). Timing results for i915-powered machines for 'time xrandr' command: Machine 1: from 0.840s to 0.290s Machine 2: from 0.315s to 0.280s Machine 3: from +/- 4s to 0.184s Timing results for HD5770 with 'time xrandr' command: Machine 4: from 3.210s to 1.060s Reviewed-by: Chris Wilson Reviewed-by: Keith Packard Tested-by: Sean Finney Tested-by: Soren Hansen Tested-by: Hernando Torque Tested-by: Mike Lothian Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41059 Signed-off-by: Eugeni Dodonov Signed-off-by: Dave Airlie Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed