[alsa-devel] [PATCH] fixed mixer range reading during probing when compiled with CONFIG_PM defined

[Daniel Schürmann]

During probing, snd_usb_autoresume() failes with -ENODEV. This brakes  
get_ctl_value() in mixer.c when rading the range values. The new  
code does not try to call snd_usb_autoresume() in this case. 
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 missleading during debug.   

Signed-off-by: Daniel Schürmann <daschuer at mixxx.org>
---
 sound/usb/mixer.c |   23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ca4739c..c2daa58 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -289,9 +289,11 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
 	int timeout = 10;
 	int idx = 0, err;
 
-	err = snd_usb_autoresume(cval->mixer->chip);
-	if (err < 0)
-		return -EIO;
+	if (!chip->probing) {	
+		err = snd_usb_autoresume(cval->mixer->chip);
+		if (err < 0)
+			return -EIO;
+	}
 	down_read(&chip->shutdown_rwsem);
 	while (timeout-- > 0) {
 		if (chip->shutdown)
@@ -333,9 +335,14 @@ 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)
-		goto error;
+	if (!chip->probing) {
+		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 +358,8 @@ 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