drm/i915: Perform link quality check unconditionally during long pulse
Apparently some DP sinks are a little nuts and cause HPD to drop intermittently during modesets. This happens eg. on an ASUS PB287Q. In oder to recover from this we can't really use the previous connector status to determine if the link needs retraining, so let's just ignore that piece of information and do the retrain unconditionally. We do of course still check whether the link is supposed to be running or not. To actually get read out the EDID and update things properly we also need to nuke the goto out added by commit 7d23e3c3 ("drm/i915: Cleaning up intel_dp_hpd_pulse"). I'm actually not sure why that was there. Perhaps to avoid an EDID read if the connector status didn't appear to change, but that sort of thing is quite racy and would have failed anyway if we failed to keep up with the hotplugs (if we missed the HPD down in between two HPD ups). And now that we take this codepath unconditionally we definitely need to drop the goto as otherwise we would never do the EDID read. v2: Drop the goto that made us skip EDID reads entirely. Doh! v3: Rebase due to locking changes s/apparely/apparently/ in the comment (Chris) Cc: stable@vger.kernel.org Cc: Manasi Navare <manasi.d.navare@intel.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Reported-by: NPalmer Dabbelt <palmer@dabbelt.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99766 References: https://lists.freedesktop.org/archives/intel-gfx/2017-February/119779.htmlSigned-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/20170412193017.21029-1-ville.syrjala@linux.intel.com
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