[PATCH 14/34] staging: comedi: das16: prevent "empty acquisition" async command

H Hartley Sweeten hsweeten at visionengravers.com
Tue Sep 9 23:15:46 UTC 2014


This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg
of 0. The (*do_cmd) then sets up and starts the command without handling the "empty
acquisition". This results in the interrupt function trying to transfer 0 data
samples.

Validate that the cmd->stop_arg is >= 1 in the (*do_cmdtest) to prevent the
"empty acquisition".

Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/staging/comedi/drivers/das16.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c
index aa52a5b..70cba3d 100644
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -692,7 +692,9 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
 		err |= cfc_check_trigger_arg_min(&cmd->convert_arg,
 						 board->ai_speed);
 
-	if (cmd->stop_src == TRIG_NONE)
+	if (cmd->stop_src == TRIG_COUNT)
+		err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
+	else	/* TRIG_NONE */
 		err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
-- 
2.0.3



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