ALSA: usb-audio: Don't set altsetting before initializing sample rate

Setting the active altsetting at changing sample rate seems
unrecommended.  The host should deselect the altsetting at first
before that, then select it again.

Tested-by: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-18-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 816fd3e5aada9660da539ffce1b0c2a12c8644e6..4501e042a944006477b263f2d9f0c9c3f9714c9b 100644 (file)
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -1223,9 +1223,10 @@ static int __snd_usb_parse_audio_interface(struct snd_usb_audio *chip,
                }
 
                /* try to set the interface... */
-               usb_set_interface(chip->dev, iface_no, altno);
+               usb_set_interface(chip->dev, iface_no, 0);
                snd_usb_init_pitch(chip, iface_no, alts, fp);
                snd_usb_init_sample_rate(chip, iface_no, alts, fp, fp->rate_max);
+               usb_set_interface(chip->dev, iface_no, altno);
        }
        return 0;
 }