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Commit 447cae58 authored by Kirill Marinushkin's avatar Kirill Marinushkin Committed by Takashi Iwai
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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: 23caaf19 ("ALSA: usb-mixer: Add support for Audio Class v2.0")
Signed-off-by: default avatarKirill Marinushkin <k.marinushkin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2bda7141

sound/usb/mixer.c

+11 −7
Original line number Diff line number Diff line
@@ -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 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request, 
		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;

}