Black screen with KABINI with kernel 4.5 with or without DAL

[Boszormenyi Zoltan]

2016-04-05 08:27 keltezéssel, Michel Dänzer írta:
> On 05.04.2016 13:07, Boszormenyi Zoltan wrote:
>> 2016-04-05 05:40 keltezéssel, Michel Dänzer írta:
>>> On 05.04.2016 00:25, Boszormenyi Zoltan wrote:
>>>> The application is Chromium in kiosk mode. The problem is that
>>>> sometimes the screen stays black after KMS kicks in.
>>> So the problem occurs even without X? Does it affect HDMI or
>>> DisplayPort, or both?
>> It occurs on both but not without X. Ctrl-Alt-F2 gives me the
>> console login prompt. My phrasing was not what I wanted to write
>> and didn't finish the sentence really. X is started very early during
>> boot so I can see the console message only momentarily while
>> the screen is still in 80x25 VGA text mode. Restarting Xorg via
>> systemctl makes it working most of the time.
>>
>> Apparently, it's not Radeon specific. We were also able to reproduce
>> it on an Intel machine, too, with internal LVDS and external VGA outputs.
> I suspect it's a client side problem then.

I have upgraded a bunch of Xorg libraries, the server to 1.18.3
and rebuilt all the drivers for the new server and the problem
doesn't occur anymore. It may be possible that we have hit some
race problems (like the one fixed in libxcb-1.11.1) but I didn't
have the time to test every piece separately. I would have done
this mass upgrade sooner or later anyway.

>   Comparing the good and bad
> dmesg output shows that Xorg is busily updating the screen in the good
> case (visible as radeon_crtc_page_flip gets called by TearFree) but not
> so in the bad case. Since the default Xorg startup behaviour is a black
> screen, it sounds like simply no client connects to Xorg / draws
> anything to the screen in the bad case. Maybe there's a race which can
> result in the client(s) starting up before Xorg, failing to establish
> the display connection, or something like that.
>
>
>> Is Xorg 1.16.4 still a supported version with new kernels?
> There's no direct version inter-dependency between Xorg and the kernel.

Noted.

Thanks for looking into it,
Zoltán Böszörményi