[Intel-gfx] [PATCH] drm/i915: Don't override output type for DDI HDMI
Takashi Iwai
tiwai at suse.de
Thu Nov 19 08:04:20 PST 2015
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 at vger.kernel.org> # v3.17+
> > Signed-off-by: Takashi Iwai <tiwai at suse.de>
>
> 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.
> 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
>
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