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. 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.