Commit a3542d1b authored by Cássio Gabriel's avatar Cássio Gabriel Committed by Takashi Iwai
Browse files

ALSA: caiaq: Fix control_put() result and cache rollback 



control_put() always returns 1 and updates cdev->control_state[]
before sending the USB command. It also ignores transport errors
from usb_bulk_msg(), snd_usb_caiaq_send_command(), and
snd_usb_caiaq_send_command_bank().

That breaks the ALSA .put() contract and can leave control_get()
reporting a cached value the device never accepted.

Return 0 for unchanged values, propagate transport failures,
and restore the cached byte when the write fails.

Fixes: 8e3cd08e ("[ALSA] caiaq - add control API and more input features")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarCássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260417-caiaq-control-put-v1-1-c37826e92447@gmail.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 4ff036f9

sound/usb/caiaq/control.c

+36 −16
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ static int control_put(struct snd_kcontrol *kcontrol, 
	struct snd_usb_caiaqdev *cdev = caiaqdev(chip->card);

	int pos = kcontrol->private_value;

	int v = ucontrol->value.integer.value[0];

	int ret;

	unsigned char cmd;



	switch (cdev->chip.usb_id) {
@@ -103,6 +104,10 @@ static int control_put(struct snd_kcontrol *kcontrol, 


	if (pos & CNT_INTVAL) {

		int i = pos & ~CNT_INTVAL;

		unsigned char old = cdev->control_state[i];



		if (old == v)

			return 0;



		cdev->control_state[i] = v;
@@ -113,9 +118,10 @@ static int control_put(struct snd_kcontrol *kcontrol, 
			cdev->ep8_out_buf[0] = i;

			cdev->ep8_out_buf[1] = v;



			usb_bulk_msg(cdev->chip.dev,

			ret = usb_bulk_msg(cdev->chip.dev,

					   usb_sndbulkpipe(cdev->chip.dev, 8),

				     cdev->ep8_out_buf, sizeof(cdev->ep8_out_buf),

					   cdev->ep8_out_buf,

					   sizeof(cdev->ep8_out_buf),

					   &actual_len, 200);

		} else if (cdev->chip.usb_id ==

			USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER)) {
@@ -128,21 +134,36 @@ static int control_put(struct snd_kcontrol *kcontrol, 
				offset = MASCHINE_BANK_SIZE;

			}



			snd_usb_caiaq_send_command_bank(cdev, cmd, bank,

			ret = snd_usb_caiaq_send_command_bank(cdev, cmd, bank,

							      cdev->control_state + offset,

							      MASCHINE_BANK_SIZE);

		} else {

			snd_usb_caiaq_send_command(cdev, cmd,

					cdev->control_state, sizeof(cdev->control_state));

			ret = snd_usb_caiaq_send_command(cdev, cmd,

							 cdev->control_state,

							 sizeof(cdev->control_state));

		}



		if (ret < 0) {

			cdev->control_state[i] = old;

			return ret;

		}

	} else {

		if (v)

			cdev->control_state[pos / 8] |= 1 << (pos % 8);

		else

			cdev->control_state[pos / 8] &= ~(1 << (pos % 8));

		int idx = pos / 8;

		unsigned char mask = 1 << (pos % 8);

		unsigned char old = cdev->control_state[idx];

		unsigned char val = v ? (old | mask) : (old & ~mask);



		snd_usb_caiaq_send_command(cdev, cmd,

				cdev->control_state, sizeof(cdev->control_state));

		if (old == val)

			return 0;



		cdev->control_state[idx] = val;

		ret = snd_usb_caiaq_send_command(cdev, cmd,

						 cdev->control_state,

						 sizeof(cdev->control_state));

		if (ret < 0) {

			cdev->control_state[idx] = old;

			return ret;

		}

	}



	return 1;
@@ -640,4 +661,3 @@ int snd_usb_caiaq_control_init(struct snd_usb_caiaqdev *cdev) 


	return ret;

}