diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2015-07-23 16:46:57 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-09-21 10:05:30 -0700 |
| commit | 815efa5df8a5fc651289a3302cd89a6dbf30ac28 (patch) | |
| tree | 87f72f9f67c021a8c4cbbd120bb1448e062d3acf /drivers/staging | |
| parent | 75882550ea3ec52c783f440f97ac4c6999916ede (diff) | |
staging: comedi: usbduxsigma: don't clobber ai_timer in command test
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()`.
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@mev.co.uk>
Reviewed-by: Bernd Porr <mail@berndporr.me.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/comedi/drivers/usbduxsigma.c | 37 |
1 files changed, 16 insertions, 21 deletions
diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c index eaa9add491df..22517deed2fd 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]); |