Re: usbaudio: Support for USB audio v2.0 devices

[Daniel Mack <daniel@caiaq.de>]

On Tue, May 18, 2010 at 10:07:57AM +0300, adelias wrote:
> On 4/5/2010 1:48 μμ, Daniel Mack wrote:
> >On Mon, May 03, 2010 at 03:49:05PM +0300, adelias wrote:
> >>On 27/4/2010 5:06 μμ, Daniel Mack wrote:
> >>>What specific configuration are you testing with? As you have such an
> >>>evaluation kit, I believe you're also provided with the XMOS development
> >>>platform - which firmware did you install to the board?
> >>>
> >>>Daniel
> >>
> >>Firmware is on 1v2. I'm not getting clicks on OSX 10.6.2 or Windows
> >>7 with the ASIO driver.
> >
> >Well, at least for OS X 10.6.2, there are problems in the class driver.
> >Do some long-time measurements with inputs and outputs to meet them.
> >
> >I would also suggest to try a newer firmware, 1v2 is rather old. If you
> >still happen to have problems, let me know and I'll have another look.
> >
> >Ironically, things don't work for me anymore currently with the Linux
> >master git + sound-2.6. I'm getting XActErrors all over the place, but
> >that's most probably not related to the driver itself but some
> >regression in the Linux USB stack I believe. Could you try that as well?
> >
> >Thanks,
> >Daniel
> >
> 
> After upgrading XMOS firmware to 1v5, although the board is
> recognized, it no longer functions with alsa. Also needs to be reset
> before it is
> recognized in Windows.

I fixed this problem now - see my latest email to Takashi. The patch
will likely be merged in a few days, but you could also give it a try by
applying it manually (see below).

And I would still appreciate some testing feedback :)


Daniel


From 3beee40982b98314f8d58c775cc8b40a8e25ce18 Mon Sep 17 00:00:00 2001
From: Daniel Mack <daniel@caiaq.de>
Date: Thu, 27 May 2010 18:28:25 +0200
Subject: [PATCH] ALSA: usb-audio: fix feature unit parser for UAC2

Fix a small off-by-one bug which causes the feature unit to announce a
wrong number of channels. This leads to illegal requests sent to the
firmware eventually.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
---
 sound/usb/mixer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 97dd176..03ce971 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1126,7 +1126,7 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
 	} else {
 		struct uac2_feature_unit_descriptor *ftr = _ftr;
 		csize = 4;
-		channels = (hdr->bLength - 6) / 4;
+		channels = (hdr->bLength - 6) / 4 - 1;
 		bmaControls = ftr->bmaControls;
 	}
 
-- 
1.7.1

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