On Wed, Sep 16, 2015 at 09:38:12PM +0200, Jiri Slaby wrote:
> From: Ian Abbott <abbotti@xxxxxxxxx>
>
> This patch has been added to the 3.12 stable tree. If you have any
> objections, please let us know.
>
Please note that this commit (and the next one) were tagged for
kernels >= 3.19.
Cheers,
--
Luís
> ===============
>
> commit 423b24c37dd5794a674c74b0ed56392003a69891 upstream
>
> `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()`.
>
> ** This backported patch also moves the code that sets up
> `devpriv->ai_sample_count` and `devpriv->ai_continuous` from
> `usbduxsigma_ai_cmdtest()` to `usbduxsigma_ai_cmd()` for the same reason
> as above. (This was not needed in the upstream commit.) **
>
> 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>
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> ---
> drivers/staging/comedi/drivers/usbduxsigma.c | 58 +++++++++++++---------------
> 1 file changed, 27 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
> index c47f4087568f..c61a1b9d7cd8 100644
> --- a/drivers/staging/comedi/drivers/usbduxsigma.c
> +++ b/drivers/staging/comedi/drivers/usbduxsigma.c
> @@ -575,37 +575,6 @@ 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 (cmd->stop_src == TRIG_COUNT) {
> - /* data arrives as one packet */
> - devpriv->ai_sample_count = cmd->stop_arg;
> - devpriv->ai_continuous = 0;
> - } else {
> - /* continuous acquisition */
> - devpriv->ai_continuous = 1;
> - devpriv->ai_sample_count = 0;
> - }
> -
> - if (err)
> - return 4;
> -
> return 0;
> }
>
> @@ -704,6 +673,33 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev,
>
> /* set current channel of the running acquisition to zero */
> s->async->cur_chan = 0;
> +
> + 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;
> + }
> +
> + if (cmd->stop_src == TRIG_COUNT) {
> + /* data arrives as one packet */
> + devpriv->ai_sample_count = cmd->stop_arg;
> + devpriv->ai_continuous = 0;
> + } else {
> + /* continuous acquisition */
> + devpriv->ai_continuous = 1;
> + devpriv->ai_sample_count = 0;
> + }
> +
> for (i = 0; i < len; i++) {
> unsigned int chan = CR_CHAN(cmd->chanlist[i]);
>
> --
> 2.5.2
>
> --
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