Hi Geert,
On 28.5.2025 11.57, Geert Uytterhoeven wrote:
On Wed, 28 May 2025 at 00:47, Eero Tamminen <o...@helsinkinet.fi> wrote:
I did boot testing on Hatari emulator with a minimal kernel config
having atari_drm enabled, atafb disabled, FB & boot logo enabled.
Under Falcon emulation:
- RGB/VGA => works fine
- Mono monitor => panic
"Kernel panic - not syncing: can't set default video mode"
>>
Under TT emulation:
- RGB/VGA => boots, but console is black[1] (palette issue?)
- Mono monitor => looks OKish[2], but has constant warnings:
-----------------------------------
WARNING: CPU: 0 PID: 1 at drivers/gpu/drm/drm_atomic_helper.c:1720
drm_atomic_helper_wait_for_vblanks+0x1a0/0x1ee
[CRTC:35:crtc-0] vblank wait timed out
I am not sure this is a bug in atari-drm, or just an issue when using
DRM on slow machines.
This does not trigger with -Os built "atafb" kernel, but happens even
with -O2 built "atari-drm" kernel. Something related to the higher (71)
HZ of the mono monitors?
(I don't think it relates to TT mono monitor's larger 1280x960
resolution, because it happens also with ST mono monitor 640x400 one.)
Btw. both kernels include:
$ grep ^CONFIG.*WATCH .config
CONFIG_WATCHDOG=y
CONFIG_WATCHDOG_CORE=y
CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED=y
CONFIG_WATCHDOG_OPEN_TIMEOUT=0
CONFIG_SOFT_WATCHDOG=y
CONFIG_WQ_WATCHDOG=y
-----------------------------------
Under 030 ST/STe emulation:
- RGB/VGA => boots, but console is black (palette issue?)
- Mono monitor => looks OK, but has constant slowpath warnings with:
"[CRTC:35:crtc-0] vblank wait timed out"
=> Any advice on the issues?
Are these regression in atari-drm, or do they happen with atafb, too?
Only the "can't set default video" issue in Falcon mono mode happens
also with "atafb".
It has neither the above vblank timeout issue in mono mode, nor
black-on-black color issue in color mode (on TT and 030 ST).
...
However, -O2 build has the downside that the resulting kernel Oopses
once it reaches user-space, if 030 data cache emulation is enabled:
----------------------------------------------------------------
Run /init as init process
...
Instruction fault at 0x0041a256
BAD KERNEL BUSERR
Interesting...
There were some extra config differences between my builds for 6.15
"atafb" and your "atari-drm-wip-rebasing" branch.
After removing the ones I could:
--------------------------------
$ diff -ub .config.old .config | grep '^[-+]C'
-CONFIG_I2C_HELPER_AUTO=y
-CONFIG_LOGO=y
-CONFIG_LOGO_LINUX_MONO=y
-CONFIG_LOGO_LINUX_VGA16=y
-------------------------------
Bus error issue went away.
=> Could there be some issue with how logo and "atari-drm" code
interact, which could manifest when reaching user-space?
Note: I haven't tried enabling logo with "atafb" + -O2 build. I could
try that later on.
- Eero
