Distorted screen with radeon driver

P

pindar

Hi,

I have installed 10.1-RELEASE to an external USB disk (gpt) on an Apple iMac (ca. 2011). Video card is a Radeon HD 6650 (which isn't mentioned in the hardware matrix). Base system works beautifully. The problem is the xorg server. When I start it up without a configuration file, my screen is split in a bizarre fashion: what should be the right side of the screen shows up at the left margin. There is a picture and description of the same problem (unfortunately no solution) at unix stackexchange. When I try to configure xorg via the Xorg -configure command, I get the error message:
Code: 
number of created screens does not match number of detected device

I deleted all references to cards, devices, screens > 0 in the generated Xorg.conf file, which is now pretty minimal, but the problem persists.

On pastebin:

my xorg.conf

and Xorg.0.log

I don't know if it's important, but I boot via EFI. Since Xorg basically works (all elements on the screen are functional, I can click menus, widgets, etc.), I hope that this is a simple configuration issue, but after much searching, I haven't found a solution yet (part of the problem being that I find it hard to imagine what would be a good keyword to describe this distortion - "split screen" is something different, obviously). I would be grateful for hints.
 
Last edited by a moderator:
The Stackexchange example uses the vesa driver, so there is not much in common with your hardware. I've seen this when two screens are auto-created and overlap.

Which window manager is being used?
Please show the output of xrandr.
 
wblock@ said:
The Stackexchange example uses the vesa driver, so there is not much in common with your hardware. I've seen this when two screens are auto-created and overlap.
Click to expand...

True, I was just relieved to find a good description of my problem.

wblock@ said:
Which window manager is being used?
Click to expand...

The default window manager that comes with xorg (I haven't installed any desktop environment yet this time); I think that's twm?

wblock@ said:
Please show the output of xrandr.
Click to expand...

Here comes:

Code: 
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP connected 1920x1080+0+0 (normal left inverted right x axis y axis) 475mm x 267mm
  1920x1080  59.93*+
  1680x1050  59.95 
  1400x1050  59.98 
  1280x1024  59.89 
  1440x900  59.89 
  1280x960  59.94 
  1280x854  59.89 
  1280x800  59.81 
  1280x720  59.86 
  1152x768  59.78 
  1024x768  59.92 
  960x540  59.82 
  800x600  59.86 
  848x480  59.66 
  720x480  59.71 
  640x480  59.38 
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
DisplayPort-2 disconnected (normal left inverted right x axis y axis)
VGA-0 disconnected (normal left inverted right x axis y axis)
 
I wanted to see if things had changed in the development version and got interesting results after installing 11-CURRENT: after installing xorg and starting it without a configuration file, I got the same distortion again. Trying to run Xorg -configure froze the computer; I had to do a hard reboot. After that, I could start up Xorg and got a beautiful output; installed xfce and had an impeccable x-session (as root). I became exuberant and installed kde4 as well; all subsequent reboots had the known distortion again, both when I run Xorg as root and as a normal user, from the console via startx or from kdm. I don't know if there is anything to be learned from this...
 
I have FreeBSD 10.1 installed on iMac 11,1 and I don't have a problem. Now I have GNOME 3 (before KDE) but my graphics card is ATI Radeon HD 4850.
I don't know if is important for you but I have in/boot/loader.conf:
Code: 
kern.vty=vt
Fernandel
 
Thanks for your suggestion. I tried that, but it's no improvement; with this setting, a get a gray screen after startx. I guess that's because I have a different graphics card...
 
After some further research: it seems that it isn't a Xorg configuration issue, but rather an issue with the kernel driver. In a console, I load the radeon module with kldload radeonkms. As soon as the module is loaded, I see the exact same distortion even in the console window, i.e. the rightmost third of the screen is cut off and inserted at the leftmost margin. Looks like the freebsd FreeBSD kernel just doesn't have support for my graphics card.
 
Maybe you can change the resolution and check again? It may be a timing issue which could be exposed that way. It would also explain why vesa and radeon drivers show the same effect.
 
Crivens said:
Maybe you can change the resolution and check again? It may be a timing issue which could be exposed that way. It would also explain why vesa and radeon drivers show the same effect.
Click to expand...
Thank you for your suggestion. I tried switching to lower resolutions, but this gives either a black/grey or a flickering screen. It really looks like a kernel/module/firmware issue to me - as I wrote, as soon as radeonkms is loaded, even the console window shows the same distortion, so this would be before any xorg.conf file is read.
 
The joy of KMS. Previously, if mode setting was buggered up, Xorg would fail and leave the console usable if you did not start it. These days, the console is also messed up so you can not really diagnose the problem. Well, what I would suggest is now changing the depth of the screen. And please take a magnifying glass and look if there is a horizontal jump on the connection when a horizontal line is drawn. If there is a jump, the start of the video memory may be miscalculated, resulting in this effect. If no jump is visible, something else may be afoot.

Any maybe you need to build drm2 without gallium support. I had serious problems with an old i915 while this was enabled.
 
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