From: Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
To: Sarah Sharp <sarah.a.sharp-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Takashi Iwai <tiwai-l3A5Bk7waGM@public.gmane.org>,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jaroslav Kysela <perex-/Fr2/VpizcU@public.gmane.org>,
alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org
Subject: Re: USB sound auto-suspend not working
Date: Wed, 18 Dec 2013 09:51:46 +0100 [thread overview]
Message-ID: <1387356706.1554.1.camel@linux-fkkt.site> (raw)
In-Reply-To: <20131217225548.GA3029@xanatos>
On Tue, 2013-12-17 at 14:55 -0800, Sarah Sharp wrote:
> Hi Oliver and Takashi,
>
> I've noticed that in the last couple kernel releases or so, I can't get
> USB webcams to suspend. It turns out that the USB sound interface is
> keeping the device active, even when the device is not playing sound.
> This goes back as far as 3.10, but I haven't tried older kernels. This
> is testing on Ubuntu 13.10.
>
> Commit 88a8516a2128a6d078a106ead48092240e8a138f "ALSA: usbaudio:
> implement USB autosuspend" went into kernel 2.6.39. The commit message
> says the device is prevented from suspending if the pcm or midi channel
> files are open.
>
> I plugged in a USB speaker, and ran lsof to see which files were open
> (output is attached). AFAICT, only the USB sound device's control files
> are open, and I don't have any midi files.
Is that sensible? In case of a webcam the problem is input, not output.
Regards
Oliver
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2013-12-18 8:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 22:55 USB sound auto-suspend not working Sarah Sharp
2013-12-17 23:07 ` Mark Brown
2013-12-18 4:15 ` Sarah Sharp
2013-12-18 8:51 ` Oliver Neukum [this message]
2013-12-18 17:29 ` Takashi Iwai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1387356706.1554.1.camel@linux-fkkt.site \
--to=oliver-gvhc2dphhpqdnm+yrofe0a@public.gmane.org \
--cc=alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org \
--cc=linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=perex-/Fr2/VpizcU@public.gmane.org \
--cc=sarah.a.sharp-VuQAYsv1563Yd54FQh9/CA@public.gmane.org \
--cc=tiwai-l3A5Bk7waGM@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).