Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757108AbcK3H7s (ORCPT ); Wed, 30 Nov 2016 02:59:48 -0500 Received: from relay1.mentorg.com ([192.94.38.131]:42627 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756664AbcK3H7Y (ORCPT ); Wed, 30 Nov 2016 02:59:24 -0500 From: Jiada Wang To: , CC: , , , Subject: [PATCH 2/3 v2] ALSA: usb-audio: avoid setting of sample rate multiple times on bus Date: Wed, 30 Nov 2016 16:59:22 +0900 Message-ID: <20161130075923.15205-3-jiada_wang@mentor.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20161130075923.15205-1-jiada_wang@mentor.com> References: <20161130075923.15205-1-jiada_wang@mentor.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1565 Lines: 49 From: Daniel Girnus ALSA usually calls the prepare function twice before starting the playback: 1. On hw_params call from userland and 2. internally when starting the stream. Some device are not able to manage this and they will stop playback if the sample rate will be configured several times over USB protocol. Signed-off-by: Jens Lorenz Signed-off-by: Jiada Wang --- sound/usb/pcm.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 44d178e..a522c9a 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -806,17 +806,18 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream) if (ret < 0) goto unlock; - iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface); - alts = &iface->altsetting[subs->cur_audiofmt->altset_idx]; - ret = snd_usb_init_sample_rate(subs->stream->chip, - subs->cur_audiofmt->iface, - alts, - subs->cur_audiofmt, - subs->cur_rate); - if (ret < 0) - goto unlock; - if (subs->need_setup_ep) { + + iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface); + alts = &iface->altsetting[subs->cur_audiofmt->altset_idx]; + ret = snd_usb_init_sample_rate(subs->stream->chip, + subs->cur_audiofmt->iface, + alts, + subs->cur_audiofmt, + subs->cur_rate); + if (ret < 0) + goto unlock; + ret = configure_endpoint(subs); if (ret < 0) goto unlock; -- 2.9.3