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author | Ian Abbott <abbotti@mev.co.uk> | 2015-09-16 14:17:14 +0100 |
---|---|---|
committer | Luis Henriques <luis.henriques@canonical.com> | 2015-09-28 10:21:33 +0100 |
commit | 101ce408692c868bd31b537b01bebe5c68968069 (patch) | |
tree | 221cf34b5170b8183e199ab5f8ef230247772f63 | |
parent | 2623fa68ac0b0d0d8981560ec7a87a5ba00c61a0 (diff) | |
download | linux-stable-101ce408692c868bd31b537b01bebe5c68968069.tar.gz linux-stable-101ce408692c868bd31b537b01bebe5c68968069.tar.bz2 linux-stable-101ce408692c868bd31b537b01bebe5c68968069.zip |
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()`.
** 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: b986be8527c7 ("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>
-rw-r--r-- | drivers/staging/comedi/drivers/usbduxsigma.c | 53 |
1 files changed, 24 insertions, 29 deletions
diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c index ccc3ef7ba55c..e2c0c54e0910 100644 --- a/drivers/staging/comedi/drivers/usbduxsigma.c +++ b/drivers/staging/comedi/drivers/usbduxsigma.c @@ -572,35 +572,6 @@ 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; - } else { - /* continuous acquisition */ - devpriv->ai_sample_count = 0; - } - - if (err) - return 4; - return 0; } @@ -700,6 +671,30 @@ 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; + } else { + /* continuous acquisition */ + devpriv->ai_sample_count = 0; + } + for (i = 0; i < len; i++) { unsigned int chan = CR_CHAN(cmd->chanlist[i]); |