From 99075df1a058bad912efdd64911b9f22e0ace537 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Thu, 30 Aug 2012 18:52:31 +0200 Subject: [PATCH] ALSA: snd-usb: fix cross-interface streaming devices Commit b5fbcea34 ("ALSA: snd-usb: move calls to usb_set_interface") saved us some unnecessary calls to snd_usb_set_interface() but ignored the fact that there is at least one device out there which operates on two endpoint in different interfaces simultaniously. Take care for this by catching the case where data and sync endpoints are located on different interfaces and calling snd_usb_set_interface() between the start of the two endpoints. Signed-off-by: Daniel Mack Reported-by: Robert M. Albrecht Cc: stable@kernel.org [v3.5+] Signed-off-by: Takashi Iwai --- sound/usb/pcm.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index e80b6687f43ae..fd5e982fc98c2 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -236,6 +236,21 @@ static int start_endpoints(struct snd_usb_substream *subs, int can_sleep) !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) { struct snd_usb_endpoint *ep = subs->sync_endpoint; + if (subs->data_endpoint->iface != subs->sync_endpoint->iface || + subs->data_endpoint->alt_idx != subs->sync_endpoint->alt_idx) { + err = usb_set_interface(subs->dev, + subs->sync_endpoint->iface, + subs->sync_endpoint->alt_idx); + if (err < 0) { + snd_printk(KERN_ERR + "%d:%d:%d: cannot set interface (%d)\n", + subs->dev->devnum, + subs->sync_endpoint->iface, + subs->sync_endpoint->alt_idx, err); + return -EIO; + } + } + snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep); ep->sync_slave = subs->data_endpoint; -- 2.39.5