ALSA: snd-usb: fix sync pipe check

Fix a bogus sanity check for sync pipe in pcm.c. This flaw was
introduced during the streaming logic refactorization.

While at it, improve the error messages that are generated in such cases.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-and-tested-by: <ben@b1c1l1.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 11 insertions, 7 deletions

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index cdf8b7601973..fc7ce7c1b4fa 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -354,17 +354,21 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
                     (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
                      get_endpoint(alts, 1)->bSynchAddress != 0 &&
                      !implicit_fb)) {
-                        snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
-                                   dev->devnum, fmt->iface, fmt->altsetting);
+                        snd_printk(KERN_ERR "%d:%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
+                                   dev->devnum, fmt->iface, fmt->altsetting,
+                                   get_endpoint(alts, 1)->bmAttributes,
+                                   get_endpoint(alts, 1)->bLength,
+                                   get_endpoint(alts, 1)->bSynchAddress);
                         return -EINVAL;
                 }
                 ep = get_endpoint(alts, 1)->bEndpointAddress;
-                if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+                if (!implicit_fb &&
+                    get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
                     (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
-                     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)) ||
-                     ( is_playback && !implicit_fb))) {
-                        snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
-                                   dev->devnum, fmt->iface, fmt->altsetting);
+                     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
+                        snd_printk(KERN_ERR "%d:%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
+                                   dev->devnum, fmt->iface, fmt->altsetting,
+                                   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
                         return -EINVAL;
                 }