Problems after replacing an ati videocard by a nvidia card (F20, both 512 MB memory)

[poma]

On 07.07.2014 14:21, Joachim Backes wrote:
> On 07/07/2014 01:06 PM, poma wrote:
>> On 07.07.2014 12:11, Joachim Backes wrote:
>>> Problem description: replacing my ati video card (DVI) by a nvidia card
>>> (DVI too) generates problems: almost unreadable (flickering) screen
>>> during boot after some boot progress (even without rhgb), no gdm login
>>> screen.
>>>
>>> The primary F20 system was installed with the ati card.
>>>
>>> Running "dracut --force" was no solution.
>>>
>>> After investigating a little bit I saw that the grub boot-parameter
>>> "video=1280x1024-24" was the culprit: replacing "video=1280x1024-24" by
>>> "video=DVI-D:1280x1024-24".
>>>
>>> Both the ati card and the nvidia card have a DVI connector.
>>>
>>> So I can't explain this weird effect. Anybody has an explanation?
>>>
>>> Kind regards
>>>
>>> Joachim Backes
>>>
>>
>> Was ist die ausgabe dieses befehls
>
> ll /sys/class/drm/ (after running the NV card!)
>
> total 0
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 card0 ->
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 card0-DVI-I-1 ->
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0/card0-DVI-I-1
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 card0-HDMI-A-1 ->
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0/card0-HDMI-A-1
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 card0-VGA-1 ->
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0/card0-VGA-1
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 controlD64 ->
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/controlD64
> lrwxrwxrwx 1 root root    0 Jul  7 14:16 ttm ->
> ../../devices/virtual/drm/ttm
> -r--r--r-- 1 root root 4096 Jul  7 14:16 version
>
>> BTW why are you using 'video=' directive?
>
> Does no come from me! It's part of /etc/default/grub (my system was
> installed using the very first F20 alpha, then updating).
>
> Kind regards
>
> Joachim Backes
>


Your problem was probably related to different video card capabilities or and due to different nomenclature of video connectors/outputs.
One example why 'video=' directive is used is to reduce the resolution and thereby increase the font displayed in a virtual terminal.
In your case it would be e.g. video=DVI-I-1:1280x1024-16 at 60
Although this can be done without it.


poma


Ref.
https://www.kernel.org/doc/Documentation/fb/modedb.txt
http://nouveau.freedesktop.org/wiki/KernelModeSetting/#forcingmodes