3 ZaphodHeads crtcs unavailable. Some outputs will stay off.
Brief summary of the problem:
Black display from initrd to the end of the boot process and ever after. What I can observe in the logs:
- radeon module and modesetting appear to load as expected,
- the 2560x1440 main and only display (eDP) is well detected,
- but
/usr/libexec/gdm-x-session[1083]: (EE) open /dev/fb0: Permission denied
- then
/usr/libexec/gdm-x-session[1083]: (II) RADEON(0): Output eDP has no monitor section
(and so for DisplayPort-0 and VGA-0). - and finally
/usr/libexec/gdm-x-session[1083]: (WW) RADEON(0): 3 ZaphodHeads crtcs unavailable. Some outputs will stay off.
I am not sure whether these lines are related one to another. The last one perfectly expresses the trouble, though ;)
needs_root_rights = yes
in /etc/X11/Xwrapper.config
gets rid of (EE) open /dev/fb0: Permission denied
, without any apparent change to the boot process (the display is still off from the beginning to the end).
Further adding radeon.uvd=0
on the kernel command line does not help either.
Hardware description:
- iMac11,1 (late 2009)
- CPU: i7 860
- GPU: [AMD/ATI] RV770/M98L [Mobility Radeon HD 4850] [1002:944a]
- System Memory: 16 Gb
- Display(s): eDP integrated 2560x1440 27"
- Type of Display Connection: embedded DP
System information:
- Distro name and Version: Pop!OS 21.10 (based on Ubuntu 21.10)
- Kernel version: Linux pop-os 5.16.15-76051615-generic #202203161444
164796402721.10~e706226 SMP PREEMPT Tue Mar 22 17 x86_64 x86_64 x86_64 GNU/Linux - Custom kernel:
- AMD official driver version:
How to reproduce the issue:
Boot from Pop!OS live USB or installed system on iMac11,1 / Radeon HD 4850
nomodeset
kernel command line option allows to install the system and openssh-server then boot with default parameters and access the system through the LAN.
Log files (for system lockups / game freezes / crashes)
dmesg Xorg.0.log__Apple_boot_+_radeon.uvd_0_+_needs_root_rights___yes_.txt