[alsa-devel] [PATCH v2] ALSA: snd-usb-audio: fixed mixer range reading during probing, when compiled with CONFIG_PM defined

[Daniel Schürmann]

During probing, snd_usb_autoresume() fails with -ENODEV. This brakes
get_ctl_value() in mixer.c when reading the range values. In the new version
snd_usb_autoresume() returns 0 in this case which brakes not the following
query. The following snd_usb_suspend() fails silently during probing anyway.
The patch also makes the error messages more significant. The original
error messages where identified as misleading during debug.


Signed-off-by: Daniel Schürmann <daschuer at mixxx.org>
---
 sound/usb/card.c  |    7 +++++--
 sound/usb/mixer.c |   11 +++++++----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 5254b18..2f55d00 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -629,9 +629,12 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 int snd_usb_autoresume(struct snd_usb_audio *chip)
 {
 	int err = -ENODEV;
-
+	
+	if (chip->probing) {
+		return 0; 
+	}
 	down_read(&chip->shutdown_rwsem);
-	if (!chip->shutdown && !chip->probing)
+	if (!chip->shutdown)
 		err = usb_autopm_get_interface(chip->pm_intf);
 	up_read(&chip->shutdown_rwsem);
 
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ca4739c..5d4f3c6 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -333,9 +333,12 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
 
 	memset(buf, 0, sizeof(buf));
 
-	ret = snd_usb_autoresume(chip) ? -EIO : 0;
-	if (ret)
+	ret = snd_usb_autoresume(chip); 
+	if (ret) {
+		snd_printk(KERN_ERR "snd_usb_autoresume() failed with %d\n", ret); 
+		ret = -EIO;		
 		goto error;
+	}
 
 	down_read(&chip->shutdown_rwsem);
 	if (chip->shutdown)
@@ -351,8 +354,8 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
 
 	if (ret < 0) {
 error:
-		snd_printk(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
-			   request, validx, idx, cval->val_type);
+		snd_printk(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d, ret = %d\n",
+			   bRequest, validx, idx, cval->val_type, ret);
 		return ret;
 	}
 
-- 
1.7.9.5