From: "Alexander E. Patrakov" <patrakov@gmail.com>
To: Lars-Peter Clausen <lars@metafoo.de>,
Raymond Yau <superquad.vortex2@gmail.com>
Cc: Takashi Iwai <tiwai@suse.de>,
ALSA Development Mailing List <alsa-devel@alsa-project.org>,
Clemens Ladisch <clemens@ladisch.de>,
David Henningsson <david.henningsson@canonical.com>,
Takashi Sakamoto <o-takashi@sakamocchi.jp>
Subject: Re: Master Plan on rewinding
Date: Mon, 22 Sep 2014 19:36:55 +0600 [thread overview]
Message-ID: <542025F7.4000708@gmail.com> (raw)
In-Reply-To: <54202219.9070102@metafoo.de>
22.09.2014 19:20, Lars-Peter Clausen wrote:
>>
>> Does this mean the those sound card can report
>> DMA_RESIDUE_GRANULARITY_BURST and driver use readl in pcm pointer
>> callback ?
>>
>> A few PCI sound cards use SG buffer including hda
>>
>> It seem that pulseaudio expect the driver support
>> DMA_RESIDUE_GRANULARITY_BURST for rewind/ timer scheduling
>
> Yes. This is why we set the BATCH flag if the granularity is not
> DMA_RESIDUE_GRANULARITY_BURST so for example pulse audio can disable
> timer scheduling.
For the record, disabling timer-based scheduling is IMHO a matter of
further discussion. As long as there is enough safeguard, I think that
timer-based scheduling can still be used, and is useful. A living proof
is the whole story with the snd-usb-audio driver where (justified)
addition of the BATCH flag was perceived as a performance regression and
not as a fix to some real and obvious problem.
I do agree that such devices need to be marked up with the BATCH flag,
so that PulseAudio chooses reasonable hardware parameters.
--
Alexander E. Patrakov
next prev parent reply other threads:[~2014-09-22 13:36 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-07 15:16 Master Plan on rewinding Alexander E. Patrakov
2014-09-07 18:38 ` Tanu Kaskinen
2014-09-07 19:05 ` Alexander E. Patrakov
2014-09-07 20:51 ` Clemens Ladisch
2014-09-08 3:06 ` Raymond Yau
2014-09-08 7:31 ` Alexander E. Patrakov
2014-09-09 8:43 ` Clemens Ladisch
2014-09-09 8:55 ` Alexander E. Patrakov
2014-09-09 9:08 ` David Henningsson
2014-09-09 9:31 ` Alexander E. Patrakov
2014-09-21 2:02 ` Raymond Yau
2014-09-22 13:20 ` Lars-Peter Clausen
2014-09-22 13:36 ` Alexander E. Patrakov [this message]
2014-09-22 13:44 ` Lars-Peter Clausen
2014-09-23 8:29 ` Raymond Yau
2014-09-23 10:22 ` Alexander E. Patrakov
2014-09-09 13:45 ` Clemens Ladisch
2014-09-09 15:55 ` Alexander E. Patrakov
2014-09-09 16:09 ` Takashi Iwai
2014-09-07 23:12 ` David Henningsson
2014-09-09 19:56 ` Pierre-Louis Bossart
2014-09-10 5:38 ` Alexander E. Patrakov
2014-09-08 7:34 ` Lars-Peter Clausen
2014-09-08 7:59 ` David Henningsson
2014-09-08 8:46 ` Alexander E. Patrakov
2014-09-08 9:26 ` David Henningsson
2014-09-08 10:21 ` Alexander E. Patrakov
2014-09-09 8:43 ` Clemens Ladisch
2014-09-11 3:49 ` Raymond Yau
2014-09-11 4:19 ` A. C. Censi
2014-09-13 9:15 ` Raymond Yau
2014-09-11 5:28 ` Alexander E. Patrakov
2014-09-11 6:21 ` Raymond Yau
2014-09-13 8:57 ` Raymond Yau
2014-09-13 10:43 ` Alexander E. Patrakov
2014-09-13 11:33 ` Raymond Yau
2014-09-13 11:36 ` Alexander E. Patrakov
2014-09-13 18:35 ` Alexander E. Patrakov
2014-09-14 11:37 ` Raymond Yau
2014-09-14 12:07 ` Alexander E. Patrakov
2014-09-15 2:43 ` Raymond Yau
2014-09-15 9:19 ` Takashi Iwai
2014-09-15 9:58 ` Alexander E. Patrakov
2014-09-15 10:08 ` Takashi Iwai
2014-09-15 17:01 ` Pierre-Louis Bossart
2014-09-15 17:14 ` Alexander E. Patrakov
2014-09-15 18:08 ` Takashi Iwai
2014-09-18 1:15 ` Raymond Yau
2014-09-21 9:22 ` Alexander E. Patrakov
2014-09-21 9:53 ` Clemens Ladisch
2014-09-21 10:56 ` Alexander E. Patrakov
2014-09-22 3:27 ` Raymond Yau
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