Reviewed-by: Bernd Porr <mail@xxxxxxxxxxxxxxx> Ian Abbott wrote:
`devpriv->ai_timer` is used while an asynchronous command is running on the AI subdevice. It also gets modified by the subdevice's `cmdtest` handler for checking new asynchronous commands (`usbduxsigma_ai_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->ai_timer` and `devpriv->ai_interval` into the subdevice's `cmd` handler, `usbduxsigma_ai_cmd()`. Note that the removed code in `usbduxsigma_ai_cmdtest()` checked that `devpriv->ai_timer` did not end up less than than 1, but that could not happen because `cmd->scan_begin_arg` had already been checked to be at least the minimum required value (at least when `cmd->scan_begin_src == TRIG_TIMER`, which had also been checked to be the case). Fixes: b986be8527c7 ("staging: comedi: usbduxsigma: tidy up analog input command support) Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # 3.19 onwards --- drivers/staging/comedi/drivers/usbduxsigma.c | 37 ++++++++++++---------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c index eaa9add..22517de 100644 --- a/drivers/staging/comedi/drivers/usbduxsigma.c +++ b/drivers/staging/comedi/drivers/usbduxsigma.c @@ -550,27 +550,6 @@ static int usbduxsigma_ai_cmdtest(struct comedi_device *dev, if (err) return 3;- /* Step 4: fix up any arguments */- - if (high_speed) { - /* - * every 2 channels get a time window of 125us. Thus, if we - * sample all 16 channels we need 1ms. If we sample only one - * channel we need only 125us - */ - devpriv->ai_interval = interval; - devpriv->ai_timer = cmd->scan_begin_arg / (125000 * interval); - } else { - /* interval always 1ms */ - devpriv->ai_interval = 1; - devpriv->ai_timer = cmd->scan_begin_arg / 1000000; - } - if (devpriv->ai_timer < 1) - err |= -EINVAL; - - if (err) - return 4; - return 0; }@@ -668,6 +647,22 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev, down(&devpriv->sem); + if (devpriv->high_speed) {+ /* + * every 2 channels get a time window of 125us. Thus, if we + * sample all 16 channels we need 1ms. If we sample only one + * channel we need only 125us + */ + unsigned int interval = usbduxsigma_chans_to_interval(len); + + devpriv->ai_interval = interval; + devpriv->ai_timer = cmd->scan_begin_arg / (125000 * interval); + } else { + /* interval always 1ms */ + devpriv->ai_interval = 1; + devpriv->ai_timer = cmd->scan_begin_arg / 1000000; + } + for (i = 0; i < len; i++) { unsigned int chan = CR_CHAN(cmd->chanlist[i]);
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