Hardware Acceleration (G400)

[johne53]

For the past couple of years I've been running 64studio (a Debian-based Linux) with the Matrox unofficial drivers, in dual-head mode. Mostly i use this setup for a digital audio workstation app called 'Ardour'. Everything's been working fine until I upgraded Ardour recently. After the upgrade, Ardour's (timeline like) display became very jerky and I noticed that my cpu was maxed out (permanently at 100% cpu cycles).

I'd never really taken much notice of cpu usage before - but after this problem, I downgraded to the previous version and noticed that my cpu had already been working at 70%, just for this one application.

Someone suggested that maybe my graphics card wasn't using the G400's hardware acceleration and they recommended that I issue this command from a Linux terminal:-

glxinfo|grep direct\ rendering

This produced the output:- Direct rendering: No. Does this mean that my driver isn't using hardware acceleration and if so, is there anything I can do to enable it?

[tuxx-home.at]

That's correct, currently there's no hw acceleration on your system. To help you find out what's wrong, I need to see your X server configuration (/etc/X11/xorg.conf) and log file (/var/log/Xorg.0.log). Please attach them to your next message and I'll see what's wrong with your configuration.

[johne53]

Okay, there seems to be a lot of info in those files, so hope you can track down the problem.

John

[tuxx-home.at]

The main problem is - which I have overlooked earlier - that you have a multihead configuration on your G-series card with Xinerama being enabled.
Hardware acceleration is not possible in this setup with the official and unofficial mga drivers:

Out of the logfiles:

Code: Select all

(WW) MGA(0): Direct rendering is not supported when Xinerama is enabled
(EE) MGA(0): [drm] DRIScreenInit failed.  Disabling DRI.


You can try to improve the performance a bit by changing a few settings in your xorg.conf

1st:
(==) MGA(0): Using AGP 1x mode

In your xorg.conf, add the following string to your device sections:

Code: Select all

Section "Device"
  [...]
  Option "AGPMode" "4"
  [...]
EndSection


This increases the AGP transfer rate and should improve performance as well.

2nd:
(**) MGA(0): Depth 24, (--) framebuffer bpp 32

Try to reduce the colour depth from 24bpp to 16bpp. To do that, change the following line in your screen sections:

Code: Select all

Section "Screen"
   [...]
   DefaultDepth   24
   [...]
EndSection


to

Code: Select all

Section "Screen"
   [...]
   DefaultDepth   16
   [...]
EndSection


After you did the changes, restart your system or kill the X server (CTRL-ALT-Backspace) for the changes to take effect.

[tuxx-home.at]

Oh, BTW, there is a way to get dualhead and proper hardware acceleration to work with the unofficial mga driver. It's called MergedFB but as to my knowledge, this feature is unfortunately broken in the current driver version.

There are several threads about MergedFB in here, so please use the search function and tell me if you found anything useful.

[johne53]

Thanks. I'll be sure to try those tips tomorrow.

BTW, how current is "current". My installed driver looks to be around 2 years old. Would the MergedFB option have been working back then?

[tuxx-home.at]

Unfortunately, 2 years old is the "current" version. No updates from Matrox since then and since I do not own a G-series card, I don't know about the state of the Xorg mga driver and wheter it's usable in the latest version, but that might also be an option for you.