Been ages since I last posted about my "efforts" in the "old forum" about getting native monitor resolutions when using puppies.
Many years ago I was using macpup which with some modelines in Xorg.cfg provided what I wanted (1920 x 1080).
With macpup, the older kernel played nicely with my radeon HD 5670 GPU, meaning no problem with kernel mode switching and the Xserver ati driver combo.
Fast forward to bionic pup, fossa pup, vanilla pup and all of them need radeon.modeset=0 for the same HD 5670 GPU, allowing kernel modesetting just leads to a black screen.
When preventing kernel mode setting the only X driver that works with these puppies is the good ol VESA driver. The VESA driver doesn't know about video outputs (just defines a default output) and modeline setting to a default output just doesn't work (presume VESA standard resolutions are the only ones allowed). Of course Xrandr is totally useless in this configuration.
When I load macpup it still works the same, so no problem with the GPU card (works great with windows as well).
Gave up in the end and replaced the old HD 5670 with a secondhand Nvidea GT 1030 and all works good (better than ever really).
Here is the thing, I have an even older AMD radeon HD 3600 series on my "internet" PC, so for fun I tried to boot the above puppies on that.
And it works fine with radeon.modeset=1, so modesetting accepted, loads kernel driver radeon and X driver ati (screen resolution choices very paltry though).
But with the ati driver I can use a modeline to output 1920 x 1080 to a detected video output (DVI-1) and I can also use Xrandr to create a session screen resolution of 1920 x 1080.
I don't get it:
The HD 5670 (evergreen GPU and terascale 2 architecture) is supposed to be compatible with kernel mode setting, seems it was with older kernels but not later ones.
The HD 3600 (RV670 and terascale 1 architecture) dates back to 2007, didn't check if it was capable of kernel mode setting, presumed it was to old for this but it works.
If I radeon.modeset=0 with the HD 3600 the behavior is as per the HD 5670 (ie kernel driver - radeon and X driver - can only be VESA).
Be interested if anyone got the HD 5670 to work without radeon.modeset=0 - I tried to configure Xorg.cfg with the ati driver (not blacklisted anywhere) and restart with radeon.modeset=1 but blackscreen is the only result. I still think I am missing something simple in setting up a working configuration to get a native screen resolution with this GPU.
back again!
