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: 8e3cd08ed8 ("[ALSA] caiaq - add control API and more input features")
Cc: stable@vger.kernel.org
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260417-caiaq-control-put-v1-1-c37826e92447@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Cássio Gabriel
2026-04-17 10:41:33 -03:00
committed by Takashi Iwai
parent 4ff036f952
commit a3542d1b30

View File

@@ -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;
@@ -113,10 +118,11 @@ 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,
usb_sndbulkpipe(cdev->chip.dev, 8),
cdev->ep8_out_buf, sizeof(cdev->ep8_out_buf),
&actual_len, 200);
ret = usb_bulk_msg(cdev->chip.dev,
usb_sndbulkpipe(cdev->chip.dev, 8),
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,
cdev->control_state + offset,
MASCHINE_BANK_SIZE);
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;
}