From: Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
To: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
Cc: Takashi Iwai <tiwai-l3A5Bk7waGM@public.gmane.org>,
Eldad Zack <eldad-v6AqZgAe4C4dvzyIwGCCOg@public.gmane.org>,
USB list <linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org,
Daniel Mack <zonque-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
James Stone <jamesmstone-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [alsa-devel] Buffer size for ALSA USB PCM audio
Date: Tue, 27 Aug 2013 22:03:26 +0200 [thread overview]
Message-ID: <521D060E.4@ladisch.de> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1308271246130.1810-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
Alan Stern wrote:
> On Tue, 27 Aug 2013, Clemens Ladisch wrote:
>> The current algorithm uses very short capture URBs to ensure that _some_
>> URB is completed as soon as possible after a period ends.
>> [...]
>> I'd suggest to keep the old calculation for capture URBs. It would
>> make sense to use longer capture URBs only if the period size is
>> relatively large.
>
> Okay. What about playback endpoints with implicit sync? The current
> driver treats them the same as capture endpoints. Is that really the
> right thing to do?
The only reason to not have an interrupt after each packet is to avoid
the interrupt overhead (for both CPU and power); shorter URBs would
result in a more precise DMA position reported to user space. If there
is already an interrupt for some capture URB (or for the feedback packet
in case of explicit feedback), we might as well handle the playback
packets so far.
Regards,
Clemens
--
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:[~2013-08-27 20:03 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-24 14:41 Buffer size for ALSA USB PCM audio Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307241013190.1313-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-24 14:54 ` Takashi Iwai
[not found] ` <s5hsiz4knyf.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-07-24 15:22 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307241108180.1313-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-24 15:26 ` Takashi Iwai
[not found] ` <s5hob9skmgs.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-07-24 15:43 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307241138180.1313-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-25 8:24 ` Takashi Iwai
[not found] ` <s5hbo5rkpwm.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-07-25 14:50 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307251043470.882-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-29 10:03 ` Takashi Iwai
[not found] ` <s5hvc3tfzt7.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-07-29 15:00 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307291041410.1479-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-29 17:12 ` Clemens Ladisch
[not found] ` <51F6A262.6010800-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2013-07-29 18:20 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307291400450.1479-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-07-29 19:23 ` Daniel Mack
[not found] ` <51F6C123.7020407-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-07-29 19:38 ` Alan Stern
2013-07-30 6:43 ` [alsa-devel] " Takashi Iwai
[not found] ` <s5hob9k5z0b.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-08-01 17:11 ` Eldad Zack
2013-08-01 17:37 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1307311645190.1546-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-12 13:22 ` [alsa-devel] " Takashi Iwai
[not found] ` <s5h7gfryrgh.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-08-12 14:53 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308121036460.1489-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-12 15:04 ` Takashi Iwai
[not found] ` <s5hvc3bx85c.wl%tiwai-l3A5Bk7waGM@public.gmane.org>
2013-08-12 16:50 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308121218590.1489-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-13 21:06 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308131659320.897-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-13 21:34 ` Daniel Mack
[not found] ` <520AA657.5010704-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-08-14 20:50 ` Eldad Zack
2013-08-15 16:06 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308151136180.905-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-18 16:56 ` Clemens Ladisch
2013-08-14 18:34 ` Clemens Ladisch
[not found] ` <520BCDBC.2060507-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2013-08-21 21:37 ` [alsa-devel] " Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308211654010.1297-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-26 18:37 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308261419100.886-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-27 6:32 ` James Stone
[not found] ` <CABRv+91ZGMHbHZFW0gYOL-zGP=HbmiJU51z-_C_2Jj+5ATisrA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-27 16:53 ` Alan Stern
2013-08-27 7:19 ` Clemens Ladisch
2013-08-27 8:01 ` Pavel Hofman
[not found] ` <521C5CC2.7030809-49v42ZqfXVBBDgjK7y7TUQ@public.gmane.org>
2013-08-27 8:11 ` [alsa-devel] " Clemens Ladisch
[not found] ` <521C5315.3030207-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2013-08-27 16:50 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308271246130.1810-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-27 20:03 ` Clemens Ladisch [this message]
[not found] ` <521D060E.4-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2013-08-27 20:11 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308271608430.940-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-28 6:41 ` Clemens Ladisch
[not found] ` <521D9BAE.2060508-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
2013-08-28 18:46 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308281441090.1541-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-29 8:10 ` James Stone
[not found] ` <CABRv+92cJPKVT9f2dyHJ_rg6sX3hP9Ct6QFas771fS79h7Eu2w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-29 15:00 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1308291059300.1170-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-08-29 17:45 ` James Stone
2013-08-29 18:42 ` Alan Stern
[not found] ` <CABRv+93oVW0rDEJnNeGyfqem2PM42b28-z9q+Ze8r7rky7szDA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-03 14:04 ` [alsa-devel] " Alan Stern
2013-09-22 21:50 ` Eldad Zack
2013-09-09 14:20 ` Daniel Mack
[not found] ` <522DD92C.4020009-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-09-09 15:36 ` Alan Stern
2013-08-13 21:54 ` Clemens Ladisch
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=521D060E.4@ladisch.de \
--to=clemens-p6gi/4k7komelga04laivw@public.gmane.org \
--cc=alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org \
--cc=eldad-v6AqZgAe4C4dvzyIwGCCOg@public.gmane.org \
--cc=jamesmstone-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org \
--cc=tiwai-l3A5Bk7waGM@public.gmane.org \
--cc=zonque-Re5JQEeQqe8AvxtiuMwx3w@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).