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Kirkx

Member

Registered: 2015-04-16

Posts: 17

[SOLVED] Fallback Video Driver for Xorg Server v1.18

I have a very basic system with only the following packages installed

- base
- base-devel
- xorg (xorg-server, xorg-server-utils, xorg-xinit, xorg-twm, xorg-xclock, xterm)

Before installing the nouveau or nvidia-340xx driver (for my GeForce 8500 GT card) I would like to try running the system using only the fallback video driver, just to see what it feels like.

Question #1

What is the official/preferred fallback driver for xorg v1.18? According to Xorg wiki it is xf86-video-vesa but this information seems to be outdated ("Driver installation" section):

https://wiki.archlinux.org/index.php/Xorg

The vesa driver apparently doesn't work with xorg after v1.15:

https://bbs.archlinux.org/viewtopic.php?id=186905

The fallback drivers suggested on the thread quoted above are:

xf86-video-modesetting
xf86-video-fbdev

The modesetting driver apparently conflicts with xorg-server 1.18.0-4:

https://www.archlinux.org/packages/extr … rg-server/

So the right fallback driver seems to be xf86-video-fbdev. Is this conclusion correct or have I missed somthing?

Question #2

Assuming that xf86-video-fbdev is indeed the best fallback driver, how can you confirm that it is properly loaded on startup?

lspci command incorrectly identifies the driver as nouveau although noveau is not even installed on the system:

lspci -k | grep VGA -A 2

01:00.0 VGA compatible controller: NVIDIA Corporation G86 [GeForce 8500 GT] (rev a1)
	Subsystem: eVga.com. Corp. Device c793
	Kernel driver in use: nouveau

pacman -Qi nouveau
error: package 'nouveau' was not found

This probably happens because mesa and mesa-libgl were pulled as dependencies during xorg installation and they are usually used together with nouveau:

pacman -Qs nouveau
local/mesa 11.1.1-1
an open-source implementaion of the OpenGL specification

The command below confirms that xf86-video-fbdev is really installed:

pacman -Qs xf86-video-fbdev
local/xf86-video-fbdev 0.4.4-5 (xorg-drivers xorg)
X.Org framebuffer video driver

Last edited by Kirkx (2016-01-22 13:56:32)

smirky

Member

From: Bulgaria

Registered: 2013-02-23

Posts: 277

Website

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

xf86-video-nouveau

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Kirkx

Member

Registered: 2015-04-16

Posts: 17

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

xf86-video-nouveau is a proper video driver, just like nvidia-340xx. I'm talking about a fallback driver, which is a generic driver that works with all GPUs but doesn't offer any advanced features (2D or 3D acceleration, etc) and normally would only be used when the proper driver fails to load for some reason.

I just want to use this basic generic driver for a while as part of Arch learning process.

loqs

Member

Registered: 2014-03-06

Posts: 17,322

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

https://www.archlinux.org/news/xorg-ser … available/ covers why the xf86-video-modesetting package is no longer needed.

Kirkx

Member

Registered: 2015-04-16

Posts: 17

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

Thanks. This answers Question #1 from my original post:

xorg-server 1.17.1 is now available
.....
following upstream, xf86-video-modesetting is now provided with xorg-server package.
.....

The answer to Question #2 still remains unclear (how can you confirm that the fallback driver was properly loaded at startup?). I have tried lsmod command. It is supposed to show which kernel modules are currently loaded, and it shows nouveau instead of xf86-video-modesetting, just like lspci command mentioned in the first post:

# empty line returned after this command
lsmod | grep xf86
.....

lsmod | grep nouveau

nouveau            1343488 1 
mxm_wmi              16384 1 nouveau
wmi                  20480 2 mxm_wmi, nouveau
video                24576 1 nouveau
ttm                  81920 1 nouveau
drm_kms_helper      106496 1 nouveau
drm                 282624 4 ttm, drm_kms_helper, nouveau
i2c_algo_bit         16384 1 nouveau
button                6384 1 nouveau

As mentioned before xf86-video-nouveau is not even installed on the system (although packages mesa and mesa-libgl are installed and they might be considered related to nouveau).

loqs

Member

Registered: 2014-03-06

Posts: 17,322

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

nouveau.ko.gz is the kernel driver and is provided by the linux package and is what is being listed in lsmod.
nouveau_drv.so is the xf86 display driver provided by the xf86-video-nouveau package.

themax

Member

Registered: 2013-05-14

Posts: 32

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

You can check Xorg.0.log which xorg driver was loaded.

Xorg.0.log is located somewhere in the dotfiles, unless you run X as root.

as loqs said, the xorg driver is not a kernel module, and the nouveau module that you see is necessary for 3D acceleration (which xf86-video-modesetting utilizes through GLAMOR)

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 29,523

Website

Re: [SOLVED] Fallback Video Driver for Xorg Server v1.18

how can you confirm that the fallback driver was properly loaded at startup?

It's not loaded at startup, it's use by Xorg, and will be in the Xorg logs.

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