[Intel-gfx] external screen goes black

[Daniel Vetter]

Hm, it's a DP screen which I've suspected (those are the kind who can
lose sync and go black). But somehow we don't get any hotplug event
when this happens - so the driver has no idea that the link went bad
and that we need to retrain. Can you please test this with this
snippet:

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 1492706..5e91242 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2580,6 +2580,8 @@ intel_dp_hot_plug(struct intel_encoder *intel_encoder)
 {
        struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);

+       printk("hotplug interrupt for DP\n");
+
        intel_dp_check_link_status(intel_dp);
 }

Also please check whether yanking and re-plugging the DP cable will
restore the display - it should.
-Daniel

On Sun, Jan 20, 2013 at 5:45 AM, Jonathan Adamczewski
<jonathan.adamczewski at gmail.com> wrote:
> Thanks for the reply, Daniel.
>
> Full traces are attached. I booted the system, ran dmesg after logging in
> through kdm.
>
> (Then I left the system while doing some other errands, hence the gap in
> time)
>
> I then started firefox, went to youtube and started watching some 4K
> resolution videos. The external screen went black in less than a minute.
> Second file is dmesg run after that - there doesn't appear to be much to
> see...
>
> There was nothing in dmesg that correlated directly with the screen going
> black. I've validated this by triggering the screen going black several
> times (that's not in the attached log, though) - there was never anything in
> dmesg that happened at the same time or that happened for tens of seconds
> thereafter.
>
>
> What's the next step for gathering information here?
>
> Many thanks
>
> Jonathan.
>
>
>
>
>
> On Sat, Jan 19, 2013 at 5:39 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
>>
>> Hi Jonathan,
>>
>> Can you please boot with drm.debug=0xe and then attach the complete
>> dmesg once right after boot, and once after the screen went black?
>>
>> Thanks, Daniel
>>
>> On Sun, Jan 20, 2013 at 1:38 AM, Jonathan Adamczewski
>> <jonathan.adamczewski at gmail.com> wrote:
>> > Hardware is a Dell XPS laptop, xorg log reports "Integrated Graphics
>> > Chipset: Intel(R) Sandybridge Mobile (GT2)"
>> >
>> > Running a custom configured 3.7.2 based kernel,
>> > xf86-video-intel-2.20.17.
>> >
>> > I'm running the internal LVDS screen at 1080p and a Dell 2713HM monitor
>> > at
>> > 2560x1440 connected via display port.
>> >
>> > Both screens run fine when X starts, but at some point the external
>> > monitor
>> > will go black. The system doesn't recognize it as being disconnected -
>> > no
>> > KDE popup asking if I want to change the monitor config as happens when
>> > pulling the DP or power on the monitor.
>> >
>> > Sometimes it will return to life after a short amount of time, most of
>> > the
>> > time it stays black indefinitely. A full power cycle of the monitor
>> > (pulling
>> > the plug) will usually bring it back to life, but typically not for
>> > long.
>> >
>> > The screen usually goes black while there's a high degree of display
>> > activity - a video playing, moving large windows around the screen,
>> > looking
>> > around in google streetview, etc. It doesn't seem to matter which screen
>> > the
>> > activity is on.
>> >
>> > It *seems* to be less likely if I run the external display at a lower
>> > resolution.
>> >
>> > There's nothing that coincides with the screen going black in dmesg or
>> > the
>> > xorg log.
>> >
>> > I've had no problems with this monitor under Windows 7 (gaming, videos,
>> > etc).
>> >
>> > What I'm looking for: ideally a simple fix :) Otherwise, any suggestions
>> > about where to look to gather more information on what could be
>> > happening
>> > here - or other places to ask for help.
>> >
>> > Many thanks
>> >
>> > jonathan.
>> >
>> > _______________________________________________
>> > Intel-gfx mailing list
>> > Intel-gfx at lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> >
>>
>>
>>
>> --
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
>
>



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch