Hello Prof. Niels R. Walet

Did you check the grub settings?

/etc/default/grub
check the line - GRUB_CMDLINE_LINUX="crashkernel=auto
rd.lvm.lv=scientific/root rd.lvm.lv=scientific/swap rhgb quiet"
make sure that nomodeset is not in the GRUB_CMDLINE_LINUX variable.
See this explaination:
https://ask.fedoraproject.org/en/question/46846/what-does-nomodeset-do/

Best Regards,

Michael Alaimo

On Wed, Jun 15, 2016 at 5:42 AM, Niels Walet
<[log in to unmask]> wrote:
> I seem to have the "radeon no UMS" error with the open source  radeon
> driver, which means it falls back to VGA.
> Quite an intriguing one, because of my 10 HP elitedesk computers (supposedly
> equivalent),  this is the only one refuses to run the proprietary fglrx
> driver. (This is on SL7.2).
> For that one, I can not get radeon to work--it loads, but gets unloaded
> again after a failure, which I guess is linked to the no UMS problem. I have
> disabled the onboard graphics, set the "nomodeset" parameters (otherwise it
> REALLY doesn't work).
> I find many discussions of similar issues all over the place, but no real
> solution. May have to run the built in graphics instead.... Any ideas? I
> tried to add a 20-radeon.conf file according to
> https://wiki.archlinux.org/index.php/ATI, and that changed things, but X now
> tries to start a number of times and fails. Any suggestions?
> Niels
>
> excerpt from /var/log/messages
> [drm] VGACON disable radeon kernel modesetting.
> [drm:radeon_init [radeon]] *ERROR* No UMS support in radeon module!
>
> excerpt from /var/log/XOrg.0.log
>        HAWAII, HAWAII, HAWAII, HAWAII, HAWAII
> [    27.334] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
> [    27.334] (II) FBDEV: driver for framebuffer: fbdev
> [    27.334] (II) VESA: driver for VESA chipsets: vesa
> [    27.334] (++) using VT number 1
>
> [    27.345] (II) [KMS] drm report modesetting isn't supported.
> [    27.345] (EE) open /dev/dri/card0: No such file or directory
> [    27.345] (WW) Falling back to old probe method for modesetting
> [    27.345] (EE) open /dev/dri/card0: No such file or directory
> [    27.345] (II) Loading sub module "fbdevhw"
> [    27.345] (II) LoadModule: "fbdevhw"
> [    27.364] (II) Loading /usr/lib64/xorg/modules/libfbdevhw.so
> [    27.379] (II) Module fbdevhw: vendor="X.Org Foundation"
> [    27.379]    compiled for 1.17.2, module version = 0.0.2
> [    27.379]    ABI class: X.Org Video Driver, version 19.0
> [    27.379] (**) FBDEV(2): claimed PCI slot 1@0:0:0
> [    27.379] (II) FBDEV(2): using default device
> [    27.379] (WW) Falling back to old probe method for vesa
> [    27.379] (EE) Screen 0 deleted because of no matching config section.
> [    27.379] (II) UnloadModule: "radeon"
> [    27.379] (EE) Screen 0 deleted because of no matching config section.
> [    27.379] (II) UnloadModule: "modesetting"
>
> ---
> Prof. Niels R. Walet                             Phone:  +44(0)1613063693
> School of Physics and Astronomy         Mobile: +44(0)7516622121
> The University of Manchester                Room 7.7, Schuster Building
> Manchester, M13 9PL,  UK
> email: [log in to unmask]   twitter: @nwalet