Looks like a CC to dri-devel got forgotten originally, so forwarding it properly. <div class="gmail_quote">---------- Forwarded message ---------- From: Eugeni Dodonov <<a href="mailto:eugeni.dodonov@intel.com">eugeni.dodonov@intel.com</a>> Date: Thu, Jan 5, 2012 at 09:34 Subject: [Intel-gfx] [PATCH 1/2] drm: give up on edid retries when i2c bus is not responding To: <a href="mailto:intel-gfx@lists.freedesktop.org">intel-gfx@lists.freedesktop.org</a> Cc: Eugeni Dodonov <<a href="mailto:eugeni.dodonov@intel.com">eugeni.dodonov@intel.com</a>> 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 <a href="https://bugs.freedesktop.org/show_bug.cgi?id=41059" target="_blank">https://bugs.freedesktop.org/show_bug.cgi?id=41059</a> 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 <<a href="mailto:chris@hchris-wilson.co.uk">chris@hchris-wilson.co.uk</a>> Reviewed-by: Keith Packard <<a href="mailto:keithp@keithp.com">keithp@keithp.com</a>> Tested-by: Sean Finney <<a href="mailto:seanius@seanius.net">seanius@seanius.net</a>> Tested-by: Soren Hansen <<a href="mailto:soren@linux2go.dk">soren@linux2go.dk</a>> Tested-by: Hernando Torque <<a href="mailto:sirius@sonnenkinder.org">sirius@sonnenkinder.org</a>> Tested-by: Mike Lothian <<a href="mailto:mike@fireburn.co.uk">mike@fireburn.co.uk</a>> Bugzilla: <a href="https://bugs.freedesktop.org/show_bug.cgi?id=41059" target="_blank">https://bugs.freedesktop.org/show_bug.cgi?id=41059</a> Signed-off-by: Eugeni Dodonov <<a href="mailto:eugeni.dodonov@intel.com">eugeni.dodonov@intel.com</a>> --- drivers/gpu/drm/drm_edid.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 3e927ce..fb6c26c 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -266,6 +266,11 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, } }; ret = i2c_transfer(adapter, msgs, 2); + if (ret == -ENXIO) { + DRM_DEBUG_KMS("drm: skipping non-existent adapter %s\n", + adapter->name); + break; + } } while (ret != 2 && --retries); return ret == 2 ? 0 : -1; -- 1.7.8 _______________________________________________ Intel-gfx mailing list <a href="mailto:Intel-gfx@lists.freedesktop.org">Intel-gfx@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/intel-gfx" target="_blank">http://lists.freedesktop.org/mailman/listinfo/intel-gfx</a> </div> -- Eugeni Dodonov<a href="http://eugeni.dodonov.net/" target="_blank"> </a>