15 Oct
2002
15 Oct
'02
8:52 p.m.
I was running through the low-latency howto and I ran into a couple
things that seem to be hindering process.
First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
I'm running debian unstable with 2.4.19.
1) DMA transer won't enable. I've enabled DMA transfers in the kernel
as suggested by the howto. However, I'm unable to turn on dma access
with hdparm. I'm told the operation is not permitted.
2) IRQ mess. dmesg lists that almost every device that is detected is
on irq 10, including the onboard sound (i8x0) and video card (nVidia).
As a result, in X, I get static and pops as the audio is delayed.
Searching further, I noticed a message saying the APIC wasn't being used
due to a buggy bios provided by Dell. This could explain why everything
is pushed to IRQ 10.
Has anyone had these problems, and more importantly, gotten around them?
I'm not sure if the bios problem mentioned is accurate for the 2650.
Looking through the kernel source, it clumps a bunch of models together.
I'm tempted to hack through that and see if it does crash...
Thanks
Greg
--- -
15 Oct
15 Oct
11:29 p.m.
2) IRQ mess. dmesg lists that almost every device
that is detected is
on irq 10, including the onboard sound (i8x0) and video card (nVidia).
As a result, in X, I get static and pops as the audio is delayed.
Searching further, I noticed a message saying the APIC wasn't being used
due to a buggy bios provided by Dell. This could explain why everything
is pushed to IRQ 10.
Has anyone had these problems, and more importantly, gotten around them?
I'm not sure if the bios problem mentioned is accurate for the 2650.
Looking through the kernel source, it clumps a bunch of models together.
I'm tempted to hack through that and see if it does crash...
I've had lots of IRQ issues on Dell servers, and the trick was normally to
disable unneeded stuff in the BIOS, most importantly, USB, if you can
afford it. (Why USB was on by default in our 2U rack mount servers is
another question entirely. :-) )
16 Oct
16 Oct
12:29 a.m.
On Tue, 2002-10-15 at 17:48, G. M. Bodnar wrote:
I was running through the low-latency howto and I ran
into a couple
things that seem to be hindering process.
First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
I'm running debian unstable with 2.4.19.
I a,m running the same setup on an IBM A31 Thinkpad, and do not have
problems with latencies. Even while running 24chs in Ardour, using a an
RME H-DSP interface. So I would venture that your problem has more to do
with Dell than Linux.
1) DMA transer won't enable. I've enabled DMA
transfers in the kernel
as suggested by the howto. However, I'm unable to turn on dma access
with hdparm. I'm told the operation is not permitted.
More evidence that it is a hardware issue. Or hardeware/software
incompatibiliy to be more politicly correct.
2) IRQ mess. dmesg lists that almost every device
that is detected is
on irq 10, including the onboard sound (i8x0) and video card (nVidia).
As a result, in X, I get static and pops as the audio is delayed.
Searching further, I noticed a message saying the APIC wasn't being used
due to a buggy bios provided by Dell. This could explain why everything
is pushed to IRQ 10.
All my devices end up on 11, but APIC takes care of things nicely.
Has anyone had these problems, and more importantly, gotten around them?
I'm not sure if the bios problem mentioned is accurate for the 2650.
Looking through the kernel source, it clumps a bunch of models together.
I'm tempted to hack through that and see if it does crash...
Thanks
Greg
--- -
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Great spirits have always encountered violent opposition from mediocre
minds.
-- Albert Einstein
They laughed at Einstein. They laughed at the Wright Brothers. But
they
also laughed at Bozo the Clown.
-- Carl Sagan
12:44 a.m.
D R Holsbeck is on permanent record as saying:
:On Tue, 2002-10-15 at 17:48, G. M. Bodnar wrote:
:> First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
:> I'm running debian unstable with 2.4.19.
:
:I a,m running the same setup on an IBM A31 Thinkpad, and do not have
:problems with latencies. Even while running 24chs in Ardour, using a an
:RME H-DSP interface. So I would venture that your problem has more to do
:with Dell than Linux.
I'm pretty certain of this actually. This is the first problem I've had
with linux+alsa in quite some time.
:> 1) DMA transer won't enable. I've enabled DMA transfers in the kernel
:> as suggested by the howto. However, I'm unable to turn on dma access
:> with hdparm. I'm told the operation is not permitted.
:
:More evidence that it is a hardware issue. Or hardeware/software
:incompatibiliy to be more politicly correct.
After a lot more poking around, it seems as if this is fixed in a
prerelease for 2.4.20. I'll have to sneaker-net some patches home with
me tonight.
:> 2) IRQ mess. dmesg lists that almost every device that is detected is
:> on irq 10, including the onboard sound (i8x0) and video card (nVidia).
:> As a result, in X, I get static and pops as the audio is delayed.
:> Searching further, I noticed a message saying the APIC wasn't being used
:> due to a buggy bios provided by Dell. This could explain why everything
:> is pushed to IRQ 10.
:
:All my devices end up on 11, but APIC takes care of things nicely.
I'll have to do some more testing around this, then. Maybe buffering
would clean things up a bit.
--- -
4:37 a.m.
"G. M. Bodnar" wrote:
I was running through the low-latency howto and I ran into a couple
things that seem to be hindering process.
First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
I'm running debian unstable with 2.4.19.
1) DMA transer won't enable. I've enabled DMA transfers in the kernel
as suggested by the howto. However, I'm unable to turn on dma access
with hdparm. I'm told the operation is not permitted.
probably a stupid question, but did you try as root ?
--
Jörn Nettingsmeier
Kurfürstenstr 49, 45138 Essen, Germany
http://spunk.dnsalias.org (my server)
http://www.linuxdj.com/audio/lad/ (Linux Audio Developers)
5:28 p.m.
Joern Nettingsmeier is on permanent record as saying:
:"G. M. Bodnar" wrote:
:>
:> 1) DMA transer won't enable. I've enabled DMA transfers in the kernel
:> as suggested by the howto. However, I'm unable to turn on dma access
:> with hdparm. I'm told the operation is not permitted.
:
:probably a stupid question, but did you try as root ?
I have missed things that obvious in the past, and probably will again,
but not this time. hdparm won't even let me read a device without root
access.
Greg
--- -
3:05 p.m.
On Tuesday 15 Oct 2002 10:48 pm, G. M. Bodnar wrote:
I was running through the low-latency howto and I ran
into a couple
things that seem to be hindering process.
First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
I'm running debian unstable with 2.4.19.
1) DMA transer won't enable. I've enabled DMA transfers in the kernel
as suggested by the howto. However, I'm unable to turn on dma access
with hdparm. I'm told the operation is not permitted.
I have a 2650 and it appears the dma problem is a bug in the 2.4.18 kernel
with certain IDE chipsets. Apparently fixed in 2.4.20
Ian
8026
days inactive
8027
days old
linux-audio-user@lists.linuxaudio.org
6 comments
5 participants
participants (5)
-
D R Holsbeck -
G. M. Bodnar -
Ian Bell -
Joern Nettingsmeier -
Michael Solberg