diff options
author | Ian Abbott <abbotti@mev.co.uk> | 2013-03-22 15:16:29 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-25 11:35:38 -0700 |
commit | e4317ce877a31dbb9d96375391c1c4ad2210d637 (patch) | |
tree | 816f2bce0fa56c52d935d68962f64c9fffb730f7 /drivers/staging | |
parent | 27ca0391fb717eecb9b9ca29ad4b9e8d7a84aba5 (diff) |
staging: comedi: s626: fix continuous acquisition
For the s626 driver, there is a bug in the handling of asynchronous
commands on the AI subdevice when the stop source is `TRIG_NONE`. The
command should run continuously until cancelled, but the interrupt
handler stops the command running after the first scan.
The command set-up function `s626_ai_cmd()` contains this code:
switch (cmd->stop_src) {
case TRIG_COUNT:
/* data arrives as one packet */
devpriv->ai_sample_count = cmd->stop_arg;
devpriv->ai_continous = 0;
break;
case TRIG_NONE:
/* continous acquisition */
devpriv->ai_continous = 1;
devpriv->ai_sample_count = 0;
break;
}
The interrupt handler `s626_irq_handler()` contains this code:
if (!(devpriv->ai_continous))
devpriv->ai_sample_count--;
if (devpriv->ai_sample_count <= 0) {
devpriv->ai_cmd_running = 0;
/* ... */
}
So `devpriv->ai_sample_count` is only decremented for the `TRIG_COUNT`
case, but `devpriv->ai_cmd_running` is set to 0 (and the command
stopped) regardless.
Fix this in `s626_ai_cmd()` by setting `devpriv->ai_sample_count = 1`
for the `TRIG_NONE` case. The interrupt handler will not decrement it
so it will remain greater than 0 and the check for stopping the
acquisition will fail.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
-rw-r--r-- | drivers/staging/comedi/drivers/s626.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/staging/comedi/drivers/s626.c b/drivers/staging/comedi/drivers/s626.c index 81a1fe661579..71a73ec5af8d 100644 --- a/drivers/staging/comedi/drivers/s626.c +++ b/drivers/staging/comedi/drivers/s626.c @@ -1483,7 +1483,7 @@ static int s626_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) case TRIG_NONE: /* continous acquisition */ devpriv->ai_continous = 1; - devpriv->ai_sample_count = 0; + devpriv->ai_sample_count = 1; break; } |