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From: Lennart Poettering <mznyfn@0pointer.de>
To: alsa-devel@alsa-project.org
Subject: Re: What does snd_pcm_delay() actually return?
Date: Fri, 13 Jun 2008 20:29:53 +0200	[thread overview]
Message-ID: <20080613182953.GA1954@tango.0pointer.de> (raw)
In-Reply-To: <s5hhcbxqp1y.wl%tiwai@suse.de>

On Fri, 13.06.08 18:26, Takashi Iwai (tiwai@suse.de) wrote:

> Wait, wait.  Please don't mix up.  The above doesn't imply anything
> about the further implementation of usb-audio driver.  What I
> suggested is, instead of hiding two pointers (hw_ptr and curr_ptr) and
> creating a complex API, simply expose them.
> 
> Now, regarding the usb-driver.  Honestly, I don't understand what you
> want to do with an extra URB.
> 
> As now, usb-audio driver handles as curr_ptr == hw_ptr.  But, in
> reality, curr_ptr = hw_ptr - samples_in_urbs.  So, in the case
> of USB-audio, hw_ptr is ahead of curr_ptr.  (And the granularity is
> samples_in_urbs).

BTW: what's the relation between periods and URBs on usb-audio right
now? I mean, the URBs should be exposed as periods to userspace,
right? But they are not right now, are they? I mean, I can set all
kinds of strange period settings for my USB device and I am pretty
sure that this is not reflected in the URB size, or am I wrong?

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

  parent reply	other threads:[~2008-06-13 18:29 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-09 19:02 What does snd_pcm_delay() actually return? Lennart Poettering
2008-06-10 14:01 ` RafałMużyło
2008-06-10 14:36 ` James Courtier-Dutton
2008-06-11 16:56 ` Takashi Iwai
2008-06-11 20:24   ` Colin Guthrie
2008-06-11 21:40     ` Tomas Carnecky
2008-06-12 10:25     ` Takashi Iwai
2008-06-12 11:51       ` Colin Guthrie
2008-06-12 12:08         ` Takashi Iwai
2008-06-12 21:00           ` Lennart Poettering
2008-06-13  6:22             ` Takashi Iwai
2008-06-12 20:52   ` Lennart Poettering
2008-06-13  6:13     ` Takashi Iwai
2008-06-13 13:51       ` Lennart Poettering
2008-06-13 13:55         ` Jaroslav Kysela
2008-06-13 14:29           ` Lennart Poettering
2008-06-13  6:59     ` Takashi Iwai
2008-06-13  8:14       ` Jaroslav Kysela
2008-06-13 10:14         ` James Courtier-Dutton
2008-06-13 12:44           ` Colin Guthrie
2008-06-13 13:06             ` Jaroslav Kysela
2008-06-13 14:48               ` Lennart Poettering
2008-06-13 15:02                 ` Jaroslav Kysela
2008-06-13 15:42                   ` Takashi Iwai
2008-06-17  0:53                     ` Eliot Blennerhassett
2008-06-13 14:38           ` Lennart Poettering
2008-06-13 15:27         ` Takashi Iwai
2008-06-13 15:44           ` Jaroslav Kysela
2008-06-13 15:59             ` Takashi Iwai
2008-06-13 16:20               ` Jaroslav Kysela
2008-06-13 16:38                 ` Takashi Iwai
2008-06-13 16:48                   ` Takashi Iwai
2008-06-13 19:55                 ` James Courtier-Dutton
2008-06-16 12:07                   ` Jaroslav Kysela
2008-06-19 17:59                     ` Lennart Poettering
2008-06-13 19:59                 ` James Courtier-Dutton
2008-06-13 14:25       ` Lennart Poettering
2008-06-13 15:55         ` Takashi Iwai
2008-06-13 16:11           ` Jaroslav Kysela
2008-06-13 16:26             ` Takashi Iwai
2008-06-13 16:47               ` Jaroslav Kysela
2008-06-13 16:52                 ` Takashi Iwai
2008-06-13 17:37                   ` Jaroslav Kysela
2008-06-13 18:23                     ` Takashi Iwai
2008-06-13 18:48                     ` Lennart Poettering
2008-06-13 18:43                 ` Lennart Poettering
2008-06-13 18:29               ` Lennart Poettering [this message]
2008-06-13 18:46                 ` Takashi Iwai
2008-06-13 19:01                   ` Lennart Poettering
2008-06-13 19:05                     ` Takashi Iwai
2008-06-13 18:22           ` Lennart Poettering
2008-06-13 18:32             ` Takashi Iwai
2008-06-14  9:51             ` James Courtier-Dutton

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