From: Clemens Ladisch <clemens@ladisch.de>
To: Mike Looijmans <mike.looijmans@topic.nl>
Cc: alsa-devel@alsa-project.org
Subject: Re: Need help diagnosing "hw_ptr skipping" message
Date: Wed, 17 Jul 2013 16:02:37 +0200 [thread overview]
Message-ID: <51E6A3FD.9070405@ladisch.de> (raw)
In-Reply-To: <51E54E82.5030402@topic.nl>
Mike Looijmans wrote:
> If I enable the "jiffies check", what is my driver doing wrong if I
> get this complaint on the kernel log while capturing:
>
> PCM: hw_ptr skipping! (pos=13677, delta=876, period=6400, jdelta=0/17/0, hw_ptr=1241601/1241601)
"hw_ptr skipping" means that the hw_ptr is skipping. Er, the value
returned by the .pointer callback moves too far in a too short amount
of time.
> hwptr log: pcmC6D0c:0 [Q]: j=19310, pos=12801/6400/25600, hwptr=1236601/1228800
> hwptr log: pcmC6D0c:0 [ ]: j=19310, pos=13677/6400/25600, hwptr=1241601/1228800
The interrupt and the userspace check happen at almost the same time
(same jiffies value), but there is suddenly a jump of 876 frames.
How does your driver compute the .pointer return value? How does this
value change?
Regards,
Clemens
next prev parent reply other threads:[~2013-07-17 14:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-02 10:55 idea: a reserve alsa plugin David Henningsson
2013-05-02 12:37 ` [pulseaudio-discuss] " Arun Raghavan
2013-05-02 13:23 ` David Henningsson
2013-05-02 14:13 ` "Negative" volume settings in a kcontrol Mike Looijmans
2013-05-06 13:22 ` Clemens Ladisch
2013-05-28 11:46 ` Mike Looijmans
2013-05-29 19:42 ` Mark Brown
2013-05-31 7:01 ` Mike Looijmans
2013-07-16 13:45 ` Need help diagnosing "hw_ptr skipping" message Mike Looijmans
2013-07-17 14:02 ` Clemens Ladisch [this message]
2013-05-02 14:28 ` idea: a reserve alsa plugin Tvrtko Ursulin
2013-05-02 14:37 ` [pulseaudio-discuss] " David Henningsson
2013-05-02 14:50 ` Tvrtko Ursulin
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