commit c04a1f17803e0d3eeada586ca34a6b436959bc20 upstream
`devpriv->ao_timer` is used while an asynchronous command is running on
the AO subdevice. It also gets modified by the subdevice's `cmdtest`
handler for checking new asynchronous commands,
`usbduxsigma_ao_cmdtest()`, which is not correct as it's allowed to
check new commands while an old command is still running. Fix it by
moving the code which sets up `devpriv->ao_timer` into the subdevice's
`cmd` handler, `usbduxsigma_ao_cmd()`.
** This backported patch also moves the code that sets up
`devpriv->ao_sample_count` and `devpriv->ao_continuous` from
`usbduxsigma_ao_cmdtest()` to `usbduxsigma_ao_cmd()` for the same reason
as above. (This was not needed in the upstream commit.) **
Note that the removed code in `usbduxsigma_ao_cmdtest()` checked that
`devpriv->ao_timer` did not end up less that 1, but that could not
happen due because `cmd->scan_begin_arg` or `cmd->convert_arg` had
already been range-checked.
Also note that we tested the `high_speed` variable in the old code, but
that is currently always 0 and means that we always use "scan" timing
(`cmd->scan_begin_src == TRIG_TIMER` and `cmd->convert_src == TRIG_NOW`)
and never "convert" (individual sample) timing (`cmd->scan_begin_src ==
TRIG_FOLLOW` and `cmd->convert_src == TRIG_TIMER`). The moved code
tests `cmd->convert_src` instead to decide whether "scan" or "convert"
timing is being used, although currently only "scan" timing is
supported.
Fixes: fb1ef622e7a3 ("staging: comedi: usbduxsigma: tidy up analog output command support")
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/usbduxsigma.c | 41 ++++++++++++----------------
1 file changed, 17 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 88c60b6..c83dcb4 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -955,10 +955,24 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
if (err)
return 3;
- /* Step 4: fix up any arguments */
+ return 0;
+}
+
+static int usbduxsigma_ao_cmd(struct comedi_device *dev,
+ struct comedi_subdevice *s)
+{
+ struct usbduxsigma_private *devpriv = dev->private;
+ struct comedi_cmd *cmd = &s->async->cmd;
+ int ret;
+ int i;
+
+ down(&devpriv->sem);
+
+ /* set current channel of the running acquisition to zero */
+ s->async->cur_chan = 0;
/* we count in timer steps */
- if (high_speed) {
+ if (cmd->convert_src == TRIG_TIMER) {
/* timing of the conversion itself: every 125 us */
devpriv->ao_timer = cmd->convert_arg / 125000;
} else {
@@ -968,12 +982,9 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
*/
devpriv->ao_timer = cmd->scan_begin_arg / 1000000;
}
- if (devpriv->ao_timer < 1)
- err |= -EINVAL;
-
if (cmd->stop_src == TRIG_COUNT) {
/* not continuous, use counter */
- if (high_speed) {
+ if (cmd->convert_src == TRIG_TIMER) {
/* high speed also scans everything at once */
devpriv->ao_sample_count = cmd->stop_arg *
cmd->scan_end_arg;
@@ -992,24 +1003,6 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
devpriv->ao_sample_count = 0;
}
- if (err)
- return 4;
-
- return 0;
-}
-
-static int usbduxsigma_ao_cmd(struct comedi_device *dev,
- struct comedi_subdevice *s)
-{
- struct usbduxsigma_private *devpriv = dev->private;
- struct comedi_cmd *cmd = &s->async->cmd;
- int ret;
- int i;
-
- down(&devpriv->sem);
-
- /* set current channel of the running acquisition to zero */
- s->async->cur_chan = 0;
for (i = 0; i < cmd->chanlist_len; ++i)
devpriv->ao_chanlist[i] = CR_CHAN(cmd->chanlist[i]);
--
2.5.1
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