Clicks in output using intel8x0 driver (and a few questions)

Clicks in output using intel8x0 driver (and a few questions)

[Josh Green]

I have a laptop with the following hardware:
P4 3.06Ghz CPU
82801DB AC'97 Audio Controller
82801DB AC'97 Modem Controller
nVidia GeForce Go5200


and software:
Linux Kernel 2.6.3 (with some ACPI patches)
Alsa 1.0.3
Glibc 2.3.2

For the most part the audio works fine, except when doing CPU intensive
tasks. When there is a lot of CPU activity the audio will sometimes
degrade into a lot of clicks and pops in the output, this can go on for
some time and vary in loudness and rate of occurrence and sometimes it
sounds like a whole audio fragment is skipped after which it will
sometimes go back into sync again.
I first noticed this in games, but afterward I noticed it when compiling
the kernel or re-encoding a movie in the background but listening to
music with XMMS (using OSS emulation). When audio gets bad with XMMS, it
is sufficient to pause and play again, in which case it will be back to
normal, and then degrade again eventually.

While I'm at it, I'll throw a couple of questions out there (hopefully
no one minds).

I was curious what the state is of the intel8x0m driver, since I have an
accursed CH4 82801DB AC'97 Modem Controller which is an HSF Conexant
device. I have it working with the linuxant.com drivers, but they are
rather unstable with the newer 2.6.4 kernel and contain binary code.
Anyone have this working with this modem?

My last question pertains to profiling. This laptop tends to have rather
large latency stutters at regular intervals (probably between 1 and 2
seconds apart). This is noticeable particularly in games and when
playing movies. I ran oprofile but the output isn't too helpful, since
it would be nicer to know exactly when a section of code was taking a
long time. Anyone know of some good strategies for tracking down latency
issues with 2.6 kernels? Thanks in advance for any help :) Cheers!
	Josh Green




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Re: Clicks in output using intel8x0 driver (and a few questions)

[Luca Capello]

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Hello,

on 03/19/04 08:03, Josh Green wrote:
> I was curious what the state is of the intel8x0m driver, since I have an
> accursed CH4 82801DB AC'97 Modem Controller which is an HSF Conexant
> device. I have it working with the linuxant.com drivers, but they are
> rather unstable with the newer 2.6.4 kernel and contain binary code.
> Anyone have this working with this modem?
yes, me :-)
    http://sourceforge.net/mailarchive/forum.php?thread_id=4059462&forum_id=1752

I used it with the daemon 'slmodemd' from the SmartLink drivers at
    ftp://ftp.smlink.com/linux/unsupported/

I don't know if there's a way to use the 'intel8x0m' without the 'slmodemd'.

Please take care that as reported in my post I used it on my old laptop (an ASUS
M3410C/M3N, Intel Centrino), while I haven't tried yet on my new one (always an
ASUS Intel Centrino, but now a M6842NWH/M6800N). I'll do my tests ASAP with the
new 2.6.5-rc1 kernel which includes the 'intel8x0m'.

Thx, bye,
Gismo / Luca
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Re: Clicks in output using intel8x0 driver (and a few questions)

[Josh Green]

On Thu, 2004-03-18 at 23:03, Josh Green wrote:
> I have a laptop with the following hardware:
> P4 3.06Ghz CPU
> 82801DB AC'97 Audio Controller
> 82801DB AC'97 Modem Controller
> nVidia GeForce Go5200
> 
> 
> and software:
> Linux Kernel 2.6.3 (with some ACPI patches)
> Alsa 1.0.3
> Glibc 2.3.2
> 
> For the most part the audio works fine, except when doing CPU intensive
> tasks. When there is a lot of CPU activity the audio will sometimes
> degrade into a lot of clicks and pops in the output, this can go on for
> some time and vary in loudness and rate of occurrence and sometimes it
> sounds like a whole audio fragment is skipped after which it will
> sometimes go back into sync again.

Thought I would reply to my message to mention that I figured out whats
causing this problem. Looks like the Intel SpeedStep is doing thermal
throttling when there is a lot of CPU activity. Another side effect of
this (besides audio degrading to a bunch of clicks) is that games will
toggle between running normal speed and then really slow (at about 4
second intervals). I ran a script to monitor changes in
/proc/acpi/processor/CPU0/throttling and it confirmed that the
throttling state was toggling between T0 and T2 (full speed and 25%
throttled respectively). So I suppose this is probably not an ALSA
problem, but I'm not sure where the problem is. I turned off speed
stepping in the BIOS, which sets the CPU frequency at 1.6Ghz (half
speed) and everything runs great. The temperature reported is much
lower, games remain normal speed and no more audio problems. So I'm not
sure if this means I have defective hardware, Linux is unable to track
the speed changes correctly or the cooling policy is throttling the CPU
instead of maxing the fan. I now have a cooling platform (3 fans powered
by USB) that I set my laptop on top of, which improves things, but the
problem still remains. I now have SpeedStep turned off, since the
overall system operation is cooler and smoother. Thanks for any
information someone might have on this problem, cheers.
	Josh Green




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