On Thu, 19 Jan 2023 10:53:23 +0100
Michal Suchanek [off-list ref] wrote:

The commit 2d681d6a23a1 ("of: Make of framebuffer devices unique")
breaks build because of wrong argument to snprintf. That certainly
avoids the runtime error but is not the intended outcome.

Also use standard device name format of-display.N for all created
devices.

Fixes: 2d681d6a23a1 ("of: Make of framebuffer devices unique")
Signed-off-by: Michal Suchanek <redacted>
---
v2: Update the device name format

Hi Michal!

Just tested your 'of: Make of framebuffer devices unique' + 'v2 of: Fix of platform build on powerpc due to bad of disaply code' on my G4 and can confirm they fix the original issue (https://bugzilla.kernel.org/show_bug.cgi?id=216095). Thanks!

Also ofdrm gets loaded now without error messages:
 # modprobe -v ofdrm
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/cfbcopyarea.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/sysimgblt.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/sysfillrect.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/cfbimgblt.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/syscopyarea.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/video/fbdev/core/cfbfillrect.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/gpu/drm/drm_kms_helper.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/gpu/drm/drm_shmem_helper.ko 
insmod /lib/modules/6.2.0-rc4-PMacG4+/kernel/drivers/gpu/drm/tiny/ofdrm.ko 

However I get no monitor output yet, despite ofdrm is loaded:
 # lsmod | grep -i drm
ofdrm                   9736  0
drm_shmem_helper        5704  1 ofdrm
drm_kms_helper        101736  1 ofdrm
cfbfillrect             2896  1 drm_kms_helper
syscopyarea             2400  1 drm_kms_helper
cfbimgblt               2256  1 drm_kms_helper
sysfillrect             2920  1 drm_kms_helper
sysimgblt               2296  1 drm_kms_helper
cfbcopyarea             2376  1 drm_kms_helper
drm                   288960  3 drm_shmem_helper,ofdrm,drm_kms_helper
drm_panel_orientation_quirks       16  1 drm

I use DRM [=m], DRM_OFDRM [=m], DRM_RADEON [=n], DRM_FBDEV_EMULATION [=y], FB [=y] and FB_OF [=n] in my kernel test .config. As far as I understand  DRM_OFDRM and FB_OF would be mutually exclusive? Also does not seem to make a difference whether FB_SIMPLE [=y] is set.

Regards,
Erhard