From: Alan Stern <stern@rowland.harvard.edu>
To: Daniel Mack <daniel@caiaq.de>
Cc: Oliver Neukum <oneukum@suse.de>,
Clemens Ladisch <clemens@ladisch.de>,
Takashi Iwai <tiwai@suse.de>, <alsa-devel@alsa-project.org>,
Greg KH <gregkh@suse.de>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
USB list <linux-usb@vger.kernel.org>,
Kernel development list <linux-kernel@vger.kernel.org>,
Chris Wright <chrisw@sous-sol.org>,
<iommu@lists.linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>,
Pedro Ribeiro <pedrib@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [alsa-devel] USB transfer_buffer allocations on 64bit systems
Date: Fri, 7 May 2010 10:45:21 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1005071042410.1804-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20100507115810.GN30801@buzzloop.caiaq.de>
On Fri, 7 May 2010, Daniel Mack wrote:
> > Or to be precise it could be done with coherent memory, but you'd risk
> > transfering partially updated buffers, as you cannot know when DMA will
> > be done and we don't guarantee that DMA will be done right as we transfer.
>
> If the memory is coherent, it should be possible. And if buffers are
> only partially updated, the audio buffer scheduling is too tight. IOW,
> the configured buffer size of audio clients in userspace is too small.
Even with coherent memory, this dynamic updating of buffer contents
isn't a good idea. There's no guarantee that coherent memory won't be
implemented using a bounce buffer during URB submission.
Alan Stern
WARNING: multiple messages have this Message-ID (diff)
From: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
To: Daniel Mack <daniel-rDUAYElUppE@public.gmane.org>
Cc: Oliver Neukum <oneukum-l3A5Bk7waGM@public.gmane.org>,
Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>,
Takashi Iwai <tiwai-l3A5Bk7waGM@public.gmane.org>,
alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org,
Greg KH <gregkh-l3A5Bk7waGM@public.gmane.org>,
Konrad Rzeszutek Wilk
<konrad.wilk-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
USB list <linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Kernel development list
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Chris Wright <chrisw-69jw2NvuJkxg9hUCZPvPmw@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Andi Kleen <andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org>,
Pedro Ribeiro <pedrib-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [alsa-devel] USB transfer_buffer allocations on 64bit systems
Date: Fri, 7 May 2010 10:45:21 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1005071042410.1804-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20100507115810.GN30801-ahpEBR4enfnCULTFXS99ULNAH6kLmebB@public.gmane.org>
On Fri, 7 May 2010, Daniel Mack wrote:
> > Or to be precise it could be done with coherent memory, but you'd risk
> > transfering partially updated buffers, as you cannot know when DMA will
> > be done and we don't guarantee that DMA will be done right as we transfer.
>
> If the memory is coherent, it should be possible. And if buffers are
> only partially updated, the audio buffer scheduling is too tight. IOW,
> the configured buffer size of audio clients in userspace is too small.
Even with coherent memory, this dynamic updating of buffer contents
isn't a good idea. There's no guarantee that coherent memory won't be
implemented using a bounce buffer during URB submission.
Alan Stern
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next prev parent reply other threads:[~2010-05-07 14:45 UTC|newest]
Thread overview: 221+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-07 9:06 USB transfer_buffer allocations on 64bit systems Daniel Mack
2010-04-07 9:06 ` Daniel Mack
[not found] ` <p2g581ef6d61004070220z1153d40ez955b356e01220848@mail.gmail.com>
2010-04-07 9:26 ` USB HID gadget driver (was: Re: USB transfer_buffer allocations on 64bit systems) Daniel Mack
2010-04-07 9:26 ` Daniel Mack
2010-04-07 14:59 ` USB transfer_buffer allocations on 64bit systems Alan Stern
2010-04-07 14:59 ` Alan Stern
2010-04-07 15:11 ` Daniel Mack
2010-04-07 15:11 ` Daniel Mack
2010-04-07 15:31 ` Greg KH
2010-04-07 15:31 ` Greg KH
2010-04-07 15:35 ` Daniel Mack
2010-04-07 15:35 ` Daniel Mack
2010-04-07 15:51 ` Greg KH
2010-04-07 15:51 ` Greg KH
2010-04-07 16:04 ` Alan Stern
2010-04-07 16:04 ` Alan Stern
2010-04-08 6:09 ` Oliver Neukum
2010-04-08 11:07 ` Daniel Mack
2010-04-08 11:07 ` Daniel Mack
2010-04-07 15:55 ` Alan Stern
2010-04-07 15:55 ` Alan Stern
2010-04-07 16:16 ` Daniel Mack
2010-04-07 16:16 ` Daniel Mack
2010-04-07 16:47 ` Alan Stern
2010-04-07 16:47 ` Alan Stern
2010-04-07 17:55 ` Takashi Iwai
2010-04-07 17:55 ` Takashi Iwai
2010-04-07 17:59 ` Daniel Mack
2010-04-07 17:59 ` Daniel Mack
2010-04-07 18:06 ` Takashi Iwai
2010-04-07 18:06 ` Takashi Iwai
2010-04-07 19:13 ` Alan Stern
2010-04-07 19:13 ` Alan Stern
2010-04-07 23:59 ` Robert Hancock
2010-04-07 23:59 ` Robert Hancock
2010-04-08 0:33 ` Greg KH
2010-04-08 0:33 ` Greg KH
2010-04-09 0:01 ` Robert Hancock
2010-04-09 16:50 ` Sarah Sharp
2010-04-09 16:50 ` Sarah Sharp
2010-04-09 23:38 ` Robert Hancock
2010-04-09 23:38 ` Robert Hancock
2010-04-10 8:34 ` [alsa-devel] " Daniel Mack
2010-04-10 8:34 ` Daniel Mack
2010-04-10 17:02 ` [alsa-devel] " Robert Hancock
2010-04-12 18:56 ` Sarah Sharp
2010-04-12 20:39 ` Robert Hancock
2010-04-12 20:39 ` Robert Hancock
2010-04-12 20:58 ` Sarah Sharp
2010-04-12 11:17 ` [PATCH] USB: rename usb_buffer_alloc() and usb_buffer_free() Daniel Mack
2010-04-12 11:17 ` Daniel Mack
2010-04-13 18:16 ` Daniel Mack
2010-04-13 18:16 ` Daniel Mack
2010-04-13 19:27 ` Alan Stern
2010-04-13 19:27 ` Alan Stern
2010-04-13 20:26 ` Greg KH
2010-04-13 21:47 ` Daniel Mack
2010-04-13 21:47 ` Daniel Mack
2010-04-07 17:52 ` USB transfer_buffer allocations on 64bit systems Takashi Iwai
2010-04-07 17:52 ` Takashi Iwai
2010-04-07 15:46 ` Alan Stern
2010-04-07 15:46 ` Alan Stern
2010-04-08 6:12 ` Oliver Neukum
2010-04-08 16:59 ` Alan Stern
2010-04-08 16:59 ` Alan Stern
2010-04-08 21:24 ` Oliver Neukum
2010-04-08 22:20 ` Alan Stern
2010-04-08 22:20 ` Alan Stern
2010-04-09 6:04 ` Oliver Neukum
2010-04-09 14:41 ` Alan Stern
2010-04-09 14:41 ` Alan Stern
2010-04-09 14:50 ` Oliver Neukum
2010-04-09 14:50 ` Oliver Neukum
2010-04-09 15:15 ` Alan Stern
2010-04-09 15:15 ` Alan Stern
2010-04-09 20:51 ` Oliver Neukum
2010-04-09 20:51 ` Oliver Neukum
2010-04-09 21:21 ` Alan Stern
2010-04-09 21:21 ` Alan Stern
2010-04-07 16:54 ` Oliver Neukum
2010-04-07 16:54 ` Oliver Neukum
2010-04-07 17:00 ` Daniel Mack
2010-04-07 17:00 ` Daniel Mack
2010-04-07 23:55 ` Robert Hancock
2010-04-07 23:55 ` Robert Hancock
2010-04-08 2:10 ` Alan Stern
2010-04-08 2:10 ` Alan Stern
2010-04-08 7:30 ` Daniel Mack
2010-04-08 7:30 ` Daniel Mack
2010-04-08 16:57 ` Alan Stern
2010-04-08 16:57 ` Alan Stern
2010-04-08 17:17 ` Pedro Ribeiro
2010-04-08 18:17 ` Alan Stern
2010-04-08 23:13 ` Pedro Ribeiro
2010-04-08 23:13 ` Pedro Ribeiro
2010-04-09 16:01 ` Alan Stern
2010-04-09 16:01 ` Alan Stern
2010-04-09 18:09 ` Daniel Mack
2010-04-09 18:19 ` Pedro Ribeiro
2010-04-09 18:19 ` Pedro Ribeiro
2010-04-09 19:34 ` Alan Stern
2010-04-09 19:34 ` Alan Stern
2010-04-09 20:14 ` Daniel Mack
2010-04-09 20:14 ` Daniel Mack
2010-04-09 20:25 ` [LKML] " Konrad Rzeszutek Wilk
2010-04-09 20:25 ` Konrad Rzeszutek Wilk
2010-04-09 21:23 ` Alan Stern
2010-04-09 21:23 ` Alan Stern
2010-04-09 22:11 ` Robert Hancock
2010-04-12 10:48 ` Daniel Mack
2010-04-12 10:48 ` Daniel Mack
2010-04-12 12:06 ` Pedro Ribeiro
2010-04-10 12:49 ` Daniel Mack
2010-04-10 12:49 ` Daniel Mack
2010-04-10 13:21 ` Pedro Ribeiro
2010-04-10 13:21 ` Pedro Ribeiro
2010-04-12 8:59 ` Andi Kleen
2010-04-12 8:59 ` Andi Kleen
2010-04-12 11:14 ` Daniel Mack
2010-04-12 11:14 ` Daniel Mack
2010-04-12 11:53 ` Andi Kleen
2010-04-12 11:53 ` Andi Kleen
2010-04-12 12:11 ` Pedro Ribeiro
2010-04-12 12:12 ` Andi Kleen
2010-04-12 12:12 ` Andi Kleen
2010-04-12 12:32 ` Daniel Mack
2010-04-12 12:47 ` Andi Kleen
2010-04-12 12:54 ` Daniel Mack
2010-04-12 12:54 ` Daniel Mack
2010-04-12 15:43 ` Andi Kleen
2010-04-12 16:17 ` Alan Stern
2010-04-12 16:17 ` Alan Stern
2010-04-12 16:29 ` Andi Kleen
2010-04-12 16:57 ` Alan Stern
2010-04-12 16:57 ` Alan Stern
2010-04-12 17:15 ` Daniel Mack
2010-04-12 17:15 ` Daniel Mack
2010-04-12 17:22 ` Andi Kleen
2010-04-12 17:22 ` Andi Kleen
2010-04-12 17:56 ` Daniel Mack
2010-04-12 17:56 ` Daniel Mack
2010-04-12 17:52 ` [LKML] " Konrad Rzeszutek Wilk
2010-04-12 17:52 ` Konrad Rzeszutek Wilk
2010-04-13 18:22 ` Daniel Mack
2010-04-13 18:22 ` Daniel Mack
2010-04-13 23:46 ` Pedro Ribeiro
2010-04-13 23:46 ` Pedro Ribeiro
2010-04-14 10:09 ` Daniel Mack
2010-04-14 10:09 ` Daniel Mack
2010-04-14 10:47 ` Pedro Ribeiro
2010-04-14 11:02 ` Pedro Ribeiro
2010-04-14 13:18 ` [LKML] " Konrad Rzeszutek Wilk
2010-04-14 14:08 ` Alan Stern
2010-04-14 14:08 ` Alan Stern
2010-04-14 16:36 ` Daniel Mack
2010-04-14 16:36 ` Daniel Mack
2010-04-14 17:21 ` Pedro Ribeiro
2010-04-14 17:21 ` Pedro Ribeiro
2010-04-14 18:23 ` Alan Stern
2010-04-14 18:27 ` Pedro Ribeiro
2010-04-14 18:53 ` Alan Stern
2010-04-15 7:35 ` Daniel Mack
2010-04-15 7:35 ` Daniel Mack
2010-04-14 18:15 ` Alan Stern
2010-04-14 18:36 ` David Woodhouse
2010-04-14 21:12 ` Pedro Ribeiro
2010-04-14 22:25 ` Chris Wright
2010-04-14 22:56 ` Pedro Ribeiro
2010-04-14 23:37 ` Chris Wright
2010-04-15 1:20 ` Pedro Ribeiro
2010-04-15 15:20 ` Alan Stern
2010-04-20 0:16 ` Pedro Ribeiro
2010-05-07 7:48 ` Daniel Mack
2010-05-07 7:48 ` Daniel Mack
2010-05-07 9:47 ` [alsa-devel] " Clemens Ladisch
2010-05-07 9:47 ` Clemens Ladisch
2010-05-07 10:24 ` [alsa-devel] " Daniel Mack
2010-05-07 10:24 ` Daniel Mack
2010-05-07 14:51 ` [alsa-devel] " Alan Stern
2010-05-07 14:51 ` Alan Stern
2010-05-10 2:50 ` FUJITA Tomonori
2010-05-10 9:21 ` David Woodhouse
2010-05-10 9:21 ` David Woodhouse
2010-05-10 14:58 ` [alsa-devel] " Alan Stern
2010-05-10 14:58 ` Alan Stern
2010-05-11 1:06 ` FUJITA Tomonori
2010-05-11 1:06 ` FUJITA Tomonori
2010-05-11 14:00 ` Alan Stern
2010-05-11 14:00 ` Alan Stern
2010-05-11 14:22 ` FUJITA Tomonori
2010-05-11 14:24 ` Konrad Rzeszutek Wilk
2010-05-11 14:38 ` FUJITA Tomonori
2010-05-11 15:04 ` Alan Stern
2010-05-11 15:04 ` Alan Stern
2010-05-11 15:34 ` FUJITA Tomonori
2010-05-11 16:06 ` Alan Stern
2010-05-11 16:09 ` Daniel Mack
2010-05-11 16:48 ` Pedro Ribeiro
2010-05-11 17:10 ` Daniel Mack
2010-05-11 17:32 ` Pedro Ribeiro
2010-05-11 17:38 ` Daniel Mack
2010-05-12 23:50 ` Pedro Ribeiro
2010-05-13 9:36 ` Daniel Mack
2010-05-14 0:17 ` Pedro Ribeiro
2010-05-11 14:57 ` Alan Stern
2010-05-11 15:05 ` Daniel Mack
2010-05-10 14:31 ` Konrad Rzeszutek Wilk
2010-05-10 14:31 ` Konrad Rzeszutek Wilk
2010-05-07 11:42 ` Oliver Neukum
2010-05-07 11:42 ` Oliver Neukum
2010-05-07 11:47 ` Oliver Neukum
2010-05-07 11:47 ` Oliver Neukum
2010-05-07 11:58 ` Daniel Mack
2010-05-07 11:58 ` Daniel Mack
2010-05-07 14:45 ` Alan Stern [this message]
2010-05-07 14:45 ` [alsa-devel] " Alan Stern
2010-04-14 18:38 ` Chris Wright
2010-04-14 20:29 ` Alan Stern
2010-04-14 21:01 ` Konrad Rzeszutek Wilk
2010-04-14 21:12 ` Pedro Ribeiro
2010-04-15 1:50 ` Alan Stern
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