Re: [PATCH 3.12 - 3.15] staging: comedi: usbduxsigma: don't clobber ao_timer in command test

[Jiri Slaby <jslaby@suse.cz>]

On 09/16/2015, 03:19 PM, Ian Abbott wrote:
> 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@mev.co.uk>

Both usbduxsigma applied to 3.12. Thanks!

-- 
js
suse labs