This is a note to let you know that I've just added the patch titled
staging: comedi: usbduxsigma: don't clobber ao_timer in command test
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From c04a1f17803e0d3eeada586ca34a6b436959bc20 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Thu, 23 Jul 2015 16:46:58 +0100
Subject: staging: comedi: usbduxsigma: don't clobber ao_timer in command test
`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()`.
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>
Reviewed-by: Bernd Porr <mail@xxxxxxxxxxxxxxx>
Reviewed-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.19 onwards
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/usbduxsigma.c | 33 ++++++++++++----------------
1 file changed, 14 insertions(+), 19 deletions(-)
diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 2d684747a639..dcb7f3037dea 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -914,25 +914,6 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
if (err)
return 3;
- /* Step 4: fix up any arguments */
-
- /* we count in timer steps */
- if (high_speed) {
- /* timing of the conversion itself: every 125 us */
- devpriv->ao_timer = cmd->convert_arg / 125000;
- } else {
- /*
- * timing of the scan: every 1ms
- * we get all channels at once
- */
- devpriv->ao_timer = cmd->scan_begin_arg / 1000000;
- }
- if (devpriv->ao_timer < 1)
- err |= -EINVAL;
-
- if (err)
- return 4;
-
return 0;
}
@@ -945,6 +926,20 @@ static int usbduxsigma_ao_cmd(struct comedi_device *dev,
down(&devpriv->sem);
+ if (cmd->convert_src == TRIG_TIMER) {
+ /*
+ * timing of the conversion itself: every 125 us
+ * at high speed (not used yet)
+ */
+ devpriv->ao_timer = cmd->convert_arg / 125000;
+ } else {
+ /*
+ * timing of the scan: every 1ms
+ * we get all channels at once
+ */
+ devpriv->ao_timer = cmd->scan_begin_arg / 1000000;
+ }
+
devpriv->ao_counter = devpriv->ao_timer;
if (cmd->start_src == TRIG_NOW) {
--
2.4.6
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