The "cb_pcidas" driver supports asynchronous commands on the analog
output (AO) subdevice for those boards that have an AO FIFO. The code
(in `cb_pcidas_ao_check_chanlist()` and `cb_pcidas_ao_cmd()`) to
validate and set up the command supports output to a single channel or
to two channels simultaneously (the boards have two AO channels).
However, the code in `cb_pcidas_auto_attach()` that initializes the
subdevices neglects to initialize the AO subdevice's `len_chanlist`
member, leaving it set to 0, but the Comedi core will "correct" it to 1
if the driver neglected to set it. This limits commands to use a single
channel (either channel 0 or 1), but the limit should be two channels.
Set the AO subdevice's `len_chanlist` member to be the same value as the
`n_chan` member, which will be 2.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/cb_pcidas.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/staging/comedi/drivers/cb_pcidas.c b/drivers/staging/comedi/drivers/cb_pcidas.c
index 48ec2ee953dc..d740c4782775 100644
--- a/drivers/staging/comedi/drivers/cb_pcidas.c
+++ b/drivers/staging/comedi/drivers/cb_pcidas.c
@@ -1342,6 +1342,7 @@ static int cb_pcidas_auto_attach(struct comedi_device *dev,
if (dev->irq && board->has_ao_fifo) {
dev->write_subdev = s;
s->subdev_flags |= SDF_CMD_WRITE;
+ s->len_chanlist = s->n_chan;
s->do_cmdtest = cb_pcidas_ao_cmdtest;
s->do_cmd = cb_pcidas_ao_cmd;
s->cancel = cb_pcidas_ao_cancel;
--
2.28.0
