On Tue, Nov 24, 2015 at 01:44:46PM +0100, Daniel Vetter wrote: > On Fri, Nov 20, 2015 at 12:18:41PM +0100, Takashi Iwai wrote: > > On Thu, 19 Nov 2015 17:04:20 +0100, > > Takashi Iwai wrote: > > > > > > On Thu, 19 Nov 2015 16:51:05 +0100, > > > Daniel Vetter wrote: > > > > > > > > On Thu, Nov 19, 2015 at 12:09:56PM +0100, Takashi Iwai wrote: > > > > > Currently a DDI port may register the DP hotplug handler even though > > > > > it's used with HDMI, and the DP HPD handler overrides the encoder > > > > > type forcibly to DP. This caused the inconsistency on a machine > > > > > connected with a HDMI monitor; upon a hotplug event, the DDI port is > > > > > suddenly switched to be handled as a DP although the same monitor is > > > > > kept connected, and this leads to the erroneous blank output. > > > > > > > > > > This patch papers over the bug by excluding the previous HDMI encoder > > > > > type from this override. This should be fixed more fundamentally, > > > > > e.g. by moving the encoder type reset from the HPD or by having > > > > > individual encoder objects for HDMI and DP. But since the bug has > > > > > been present for a long time (3.17), it's better to have a > > > > > quick-n-dirty fix for now, and keep working on a cleaner fix. > > > > > > > > > > Bugzilla: http://bugzilla.opensuse.org/show_bug.cgi?id=955190 > > > > > Fixes: 0e32b39ceed6 ('drm/i915: add DP 1.2 MST support (v0.7)') > > > > > Cc: <stable@xxxxxxxxxxxxxxx> # v3.17+ > > > > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > > > > > > > > If you plug in a hmid screen (using a level-shifter adapter), then a DP > > > > screen, does still everything work? > > > > > > That was my slight concern, too, although it seems working as long as > > > I tested several HSW machines. Maybe better to double-check. > > > > I checked again some machines, and they all seem working. > > > > Actually the encoder type is set again in each detection function > > (intel_hdmi_detect(), intel_dp_detect()) no matter with or without my > > workaround. The problem happens when a HPD is triggered only to DP > > while the HDMI is kept on. Then intel_hdmi_detect() won't be called > > so the wrongly overridden encoder type remains. > > > > Why the override is still needed in intel_dp_hpd_pulse() isn't clear > > to me, but at least it influences on the port power domain handling. > > And my change won't affect in this regard. > > My suspicion is that we need this to reset between > INTEL_OUTPUT_DISPLAYPORT and INTEL_OUTPUT_DP_MST. INTEL_OUTPUT_DP_MST is the type for fake mst encoders, and those don't have a .hpd_pulse() hook to begin with. -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
