Startx only displays GUI if killed and started again

The 2600XT is actually the architecture before GCN, called TeraScale. That means that the ATI driver should be used according to Xorg AMD .

Thanks for the additional information. Now knowing it’s TeraScale, the choice of the ATI driver becomes obvious; or, in this case, the open source radeon, if I’m reading that correctly.

There’s likely something useful here:

Had a 2009 Packard Bell EasyNote with Radeon HD 4225 that run well on 5.15LTS and radeon:

Graphics:
  Device-1: AMD RS880M [Mobility Radeon HD 4225/4250] driver: radeon
    v: kernel

After the mobo died I put the ssd in an intel/nvidia laptop without issues. However, at a recent mkinitcpio.conf.pacnew meld on that system I discovered “amdgpu” in the modules line (needs amd-ucode installed). I’m sure I never touched the file when it was in the EasyNote. Maybe worth replicating that. Also, make sure it’s got ‘kms’ in the ‘hooks’ line.

Two more things to try, since the Radeon HD 2600 XT is slightly older:

  • add the kernel parameter radeon.dpm=0
  • add the kernel parameter radeon.pcie_gen2=0
    I’d try one after the other, then both (and of course revert if unsuccessful). ATI - ArchWiki

Thank you for your suggestions.

kms is in the hooks line.

Unfortunately, neither radeon.dpm=0 nor radeon.pcie_gen2=0 nor a combination of both solved the problem.

I’ll make my way through the ATI page at ArchWiki and report in case anything interesting happens.

I created /etc/X11/xorg.conf.d/20-radeon.conf with the following content:

Section "OutputClass"
    Identifier "Radeon"
    MatchDriver "radeon"
    Driver "radeon"
    Option "AccelMethod" "glamor"
    Option "TearFree" "on"
    Option "ColorTiling" "on"
    Option "ColorTiling2D" "on"
    Option "ShadowPrimary" "on"
EndSection

Now I consistently get an only slightly warped image of the greeter from which I can switch to tty, kill X and start X again. Then, everything runs flawlessly. Still, not optimal…

grep "(WW)" /var/log/Xorg.0.log of the warped image of the greeter gives:

[    21.885] (WW) The directory "/usr/share/fonts/misc" does not exist.
[    21.886] (WW) The directory "/usr/share/fonts/OTF" does not exist.
[    21.886] (WW) The directory "/usr/share/fonts/Type1" does not exist.
[    21.904] (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
[    21.933] (WW) Warning, couldn't open module fbdev
[    21.943] (WW) Falling back to old probe method for modesetting
[    22.313] (WW) RADEON(0): KMS Pageflipping: disabled because of ShadowPrimary
[    22.340] (WW) RADEON(0): 3 ZaphodHeads crtcs unavailable. Some outputs will stay off.
[    22.443] (WW) RADEON(0): Option "MigrationHeuristic" is not used