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ALSA: usb-audio: Fix UAC2 get_ctl request with a RANGE attribute 

The layout of the UAC2 Control request and response varies depending on
the request type. With the current implementation, only the Layout 2
Parameter Block (with the 2-byte sized RANGE attribute) is handled
properly. For the Control requests with the 1-byte sized RANGE attribute
(Bass Control, Mid Control, Tremble Control), the response is parsed
incorrectly.

This commit:
* fixes the wLength field value in the request
* fixes parsing the range values from the response

Fixes: 23caaf19b1 ("ALSA: usb-mixer: Add support for Audio Class v2.0")
Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Kirill Marinushkin 2018-01-29 06:37:55 +01:00 committed by Takashi Iwai
parent 2bda7141b8
commit 447cae58ce
1 changed files with 11 additions and 7 deletions
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18
sound/usb/mixer.c
View File

@ -347,17 +347,20 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
int validx, int *value_ret)
{
struct snd_usb_audio *chip = cval->head.mixer->chip;
unsigned char buf[4 + 3 * sizeof(__u32)]; /* enough space for one range */
/* enough space for one range */
unsigned char buf[sizeof(__u16) + 3 * sizeof(__u32)];
unsigned char *val;
int idx = 0, ret, size;
int idx = 0, ret, val_size, size;
__u8 bRequest;
val_size = uac2_ctl_value_size(cval->val_type);
if (request == UAC_GET_CUR) {
bRequest = UAC2_CS_CUR;
size = uac2_ctl_value_size(cval->val_type);
size = val_size;
} else {
bRequest = UAC2_CS_RANGE;
size = sizeof(buf);
size = sizeof(__u16) + 3 * val_size;
}
memset(buf, 0, sizeof(buf));
@ -390,16 +393,17 @@ error:
val = buf + sizeof(__u16);
break;
case UAC_GET_MAX:
val = buf + sizeof(__u16) * 2;
val = buf + sizeof(__u16) + val_size;
break;
case UAC_GET_RES:
val = buf + sizeof(__u16) * 3;
val = buf + sizeof(__u16) + val_size * 2;
break;
default:
return -EINVAL;
}
*value_ret = convert_signed_value(cval, snd_usb_combine_bytes(val, sizeof(__u16)));
*value_ret = convert_signed_value(cval,
snd_usb_combine_bytes(val, val_size));
return 0;
}