staging: comedi: usbduxsigma: don't clobber ai_timer in command test

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commit 423b24c37d 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` 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: b986be8527 ("staging: comedi: usbduxsigma: tidy up analog input command support)
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

...

This commit is contained in:

Ian Abbott 2015-09-16 14:17:14 +01:00 • committed by Luis Henriques

parent 2623fa68ac

commit 101ce40869

1 changed files with 24 additions and 29 deletions

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drivers/staging/comedi/drivers/usbduxsigma.c

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