From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: [PATCH v5] ALSA: usb: Work around CM6631 sample rate change bug Date: Wed, 03 Apr 2013 12:15:49 +0200 Message-ID: <515C0155.4090009@ladisch.de> References: <20130326211004.GD18838@pvv.ntnu.no> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by alsa0.perex.cz (Postfix) with ESMTP id A7120265367 for ; Wed, 3 Apr 2013 12:15:53 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: Torstein Hegge , alsa-devel@alsa-project.org, zonque@gmail.com List-Id: alsa-devel@alsa-project.org Takashi Iwai wrote: > Torstein Hegge wrote: >> The C-Media CM6631 USB receiver doesn't respond to changes in sample rate >> while the interface is active. The same behavior is observed in other UAC2 >> hardware like the VIA VT1731. >> >> Reset the interface after setting the sampling frequency on sample rate >> changes, to ensure that the sample rate set by snd_usb_init_sample_rate() is >> used. Otherwise, the device will try to use the sample rate of the previous >> stream, causing distorted sound on sample rate changes. >> >> The reset is performed for all UAC2 devices, as it should not affect a >> standards compliant device, but it is only necessary for C-Media CM6631, >> VIA VT1731 and possibly others. >> >> Failure to read sample rate from the device is not handled as an error in >> set_sample_rate_v2(), as (permanent or intermittent) failure to read sample >> rate isn't essential for a successful sample rate set. >> >> Signed-off-by: Torstein Hegge > > What about the latest status of the patch? > > If both Clemens and Daniel are happy with it, I can apply it for the > next 3.9-rc. Acked-by: Clemens Ladisch with or without this change: > Though, it would be nicer if two identical calls of snd_usb_ctl_msg > can be put into a single function, Regards, Clemens