Reviewed-by: Bernd Porr <mail@xxxxxxxxxxxxxxx> Ian Abbott wrote:
`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> Cc: <stable@xxxxxxxxxxxxxxx> # 3.19 onwards --- 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 22517de..dc0b25a 100644 --- a/drivers/staging/comedi/drivers/usbduxsigma.c +++ b/drivers/staging/comedi/drivers/usbduxsigma.c @@ -912,25 +912,6 @@ 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; }@@ -943,6 +924,20 @@ 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) {
-- http://www.berndporr.me.uk http://www.linux-usb-daq.co.uk http://www.imdb.com/name/nm3293421/ +44 (0)7840 340069 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
