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authorDaniel Mack <daniel@caiaq.de>2010-06-11 17:34:22 +0200
committerTakashi Iwai <tiwai@suse.de>2010-06-11 18:06:35 +0200
commite8bdb6bbab60a8731f21823c86391f176d052348 (patch)
tree3ee6716941a195b4a1110ff5320c3ab9f29c77a7
parent67c103664a06fa590f2990c01773dfa1dffcefdc (diff)
ALSA: usb-audio: fix UAC2 control value queries
For RANGE requests, we should only query as much bytes as we're in fact interested in. For CUR requests, we shouldn't confuse the firmware with an overlong request but just ask for 2 bytes. This might need fixing in the future as it's not entirely clear when to dispatch 1-byte, 2-byte and 4-byte request blocks. For now, we assume everything is coded in 16bit - this works for all firmware implementations I've seen. Signed-off-by: Daniel Mack <daniel@caiaq.de> Reported-by: Alex Lee <alexlee188@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/usb/mixer.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index a060d005e20..6939d0f517d 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -297,20 +297,27 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v
static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int validx, int *value_ret)
{
- unsigned char buf[14]; /* enough space for one range of 4 bytes */
+ unsigned char buf[2 + 3*sizeof(__u16)]; /* enough space for one range */
unsigned char *val;
- int ret;
+ int ret, size;
__u8 bRequest;
- bRequest = (request == UAC_GET_CUR) ?
- UAC2_CS_CUR : UAC2_CS_RANGE;
+ if (request == UAC_GET_CUR) {
+ bRequest = UAC2_CS_CUR;
+ size = sizeof(__u16);
+ } else {
+ bRequest = UAC2_CS_RANGE;
+ size = sizeof(buf);
+ }
+
+ memset(buf, 0, sizeof(buf));
ret = snd_usb_ctl_msg(cval->mixer->chip->dev,
usb_rcvctrlpipe(cval->mixer->chip->dev, 0),
bRequest,
USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
validx, cval->mixer->ctrlif | (cval->id << 8),
- buf, sizeof(buf), 1000);
+ buf, size, 1000);
if (ret < 0) {
snd_printk(KERN_ERR "cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
@@ -318,6 +325,8 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, int v
return ret;
}
+ /* FIXME: how should we handle multiple triplets here? */
+
switch (request) {
case UAC_GET_CUR:
val = buf;