21 Jul
2004
21 Jul
'04
4:04 p.m.
On Wed, 2004-07-21 at 03:53, Florian Schmidt wrote:
On Tue, 20 Jul 2004 20:32:37 -0400
Lee Revell <rlrevell(a)joe-job.com> wrote:
The mga dri kernel driver shares a problem with the radeon (which I use
a lot) and the r128 drivers. They have high latency points that reach
10-15 msecs in normal operation[*]. I have a very old patch (not mine, I
don't quite remember where I got it from) that solves this, but it is
not a "legal" patch in the sense that in schedules with a lock held. It
seems to work but it will lock the computer at some point. AFAIK there
is no proper patch for this latency point at this time. Turning off
acceleration should get rid of the latency spikes with the usual
tradeoff of slow video performance.
-- Fernando
[*] with the (bad) patch:
http://ccrma.stanford.edu/~nando/latencytest/20040323/2.6.4-1.279.ll.ccrma.…
without the patch:
http://ccrma.stanford.edu/~nando/latencytest/20040323/2.6.4-1.279.ll.ccrma/
Yes, this is important. One problem I had
recently with the Via EPIA
board was that unless 2D acceleration was disabled by setting 'Option
"NoAccel"' in /etc/X11/XF86Config-4, overloading the X server would
cause interrupts from the soundcard to be completely disabled for tens
of milliseconds. Users should keep in mind that by using 2D or 3D
hardware acceleration in X, you are allowing the X server to directly
access hardware, which can have very bad results if the driver is
buggy. I am not sure the kernel can do anything about this.
Hi,
interesting that you mention the Xserver. I use a dual graphics card setup atm
[Nvidia GF3 TI and some matrox pci card]. The nvidia card seems to work flawlessly
even with HW accelleration [i use nvidias evil binary only drivers]. The matrox
card OTH disturbs the soundcard severely. Whenever i have activity on my second
monitor i get sound artefacts in jack's output [no cracklling, it's rather as
if the volume is set to 0 for short moments and then back to normal]. There's
a certain chance that this artefact produces an xrun. I suppose it's because
the card is on the pci bus.