From: Eugeni Dodonov <eugeni.dodo...@intel.com> This is the the forth iteration of potential fixes for slow edid detection issues over non-existent outputs (https://bugs.freedesktop.org/show_bug.cgi?id=41059) - the previous versions were posted to the bug and were used mostly for debugging the problem.
After investigation, I came to think on two different ways to fix the issue: in PATCH1, I added a check for the return value of i2c_transfer - and, if it is -ENXIO, we give up on further attempts as the bus is not there. A drawback to this approach is that it affects all the devices out there which use drm_get_edid. From my testing, the -ENXIO gave no false positives, but I haven't tested it on non-Intel cards. The second patch does a similar procedure within the i915 driver. It adds a new function - intel_drm_get_valid_edid - which attempts to do a simple i2c transfer over the bus prior to calling drm_get_edid. In case such transfer fails with -ENXIO, it is a signal that the bus is not there, so we shouldn't waste any time trying to communicate with it further. Note that those patches provide lots of dmesg pollution - I just wanted to send them out to get an overall feedback on the proposed approach. Eugeni Dodonov (2): Give up on edid retries when i2c tells us that bus is not there Check if the bus is valid prior to discovering edid. drivers/gpu/drm/drm_edid.c | 5 +++++ drivers/gpu/drm/i915/intel_dp.c | 4 ++-- drivers/gpu/drm/i915/intel_drv.h | 2 ++ drivers/gpu/drm/i915/intel_hdmi.c | 4 ++-- drivers/gpu/drm/i915/intel_i2c.c | 33 +++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_lvds.c | 2 +- drivers/gpu/drm/i915/intel_modes.c | 2 +- drivers/gpu/drm/i915/intel_sdvo.c | 4 ++-- 8 files changed, 48 insertions(+), 8 deletions(-) -- 1.7.6.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx