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. Takashi > > > We rely upon the detection code to correctly adjust the encoder type, > > otherwise the subsequent modeset will pick the wrong code (even when > > userspace asked the kernel to light up the right connector). I'm not sure > > whether this is now broken ... > > I guess the only case this might matter is MST, as the encoder > override didn't exist before the MST support patch, so the non-MST > case should keep working even with this change. > > > thanks, > > Takashi > > > -Daniel > > > > > --- > > > drivers/gpu/drm/i915/intel_dp.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > > > index 09bdd94ca3ba..d34e64300d66 100644 > > > --- a/drivers/gpu/drm/i915/intel_dp.c > > > +++ b/drivers/gpu/drm/i915/intel_dp.c > > > @@ -5153,7 +5153,8 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd) > > > enum intel_display_power_domain power_domain; > > > enum irqreturn ret = IRQ_NONE; > > > > > > - if (intel_dig_port->base.type != INTEL_OUTPUT_EDP) > > > + if (intel_dig_port->base.type != INTEL_OUTPUT_EDP && > > > + intel_dig_port->base.type != INTEL_OUTPUT_HDMI) > > > intel_dig_port->base.type = INTEL_OUTPUT_DISPLAYPORT; > > > > > > if (long_hpd && intel_dig_port->base.type == INTEL_OUTPUT_EDP) { > > > -- > > > 2.6.3 > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch > > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
