[Dev] [Assist] Fwd: Re: Xorg Problem with Radeon

Jorge Lopez jorginho at riseup.net
Fri Sep 12 13:15:06 GMT 2014

On 12/09/14 13:03, André Silva wrote:
> On 09/12/2014 07:35 AM, Jorge Lopez wrote:
> > I don't need AGP support because my card is PCI-E.
> So, i think you have have problems with the resolution. If you are
> doing early KMS, you must construct your own EDID or you will run into
> problems.
> The makefile included in the Documentation/EDID sources of the kernel. [0]
> It says "The code (see drivers/gpu/drm/drm_edid_load.c) contains
> built-in data sets for commonly used screen resolutions (800x600,
> 1024x768, 1280x1024, 1600x1200, 1680x1050, 1920x1080) as binary blobs,
> but the kernel source tree does not contain code to create these
> data.", therefore it is nonfree! It should be reported to Linux-libre
> developers :S
> So, in my opinion you should follow the Late start mode [1] and pay
> attention on the first part that says
> "Remove all vga= options from the kernel line in the bootloader
> configuration file. Using other framebuffer drivers (such as uvesafb
> or radeonfb) will conflict with KMS. Remove any framebuffer related
> modules from /etc/mkinitcpio.conf. video= can now be used in
> conjunction with KMS."
> There is a part that says "video= can now be used in conjunction with
> KMS", if the problem persists specifying resolution with video=
> command line may be useful. A mode can be forced on the kernel command
> line, but the command line option video is poorly documented in the
> DRM case. Bits and pieces on how to use it can be found in [2][3] or
> if you are using GRUB, check [4]
> [0]:https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/plain/Documentation/EDID/HOWTO.txt
> [1]:https://wiki.archlinux.org/index.php/ATI#Late_start
> [2]:http://cgit.freedesktop.org/nouveau/linux-2.6/tree/Documentation/fb/modedb.txt
> [3]:http://cgit.freedesktop.org/nouveau/linux-2.6/tree/drivers/gpu/drm/drm_fb_helper.c
> [4]:https://wiki.archlinux.org/index.php/GRUB#Setting_the_framebuffer_resolution
I use de KMS start later and I edit boot options in /etc/default/grub

Now the radeon works without nomodeset in boot options

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