From 8c602c498cd88faa78e17acc7efa29a36012e728 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 9 Sep 2014 16:16:00 -0700 Subject: [PATCH] staging: comedi: rtd520: prevent "empty acquisition" async command 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 Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/rtd520.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/staging/comedi/drivers/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c index f0bf3edf5a31..7d4cb140959c 100644 --- a/drivers/staging/comedi/drivers/rtd520.c +++ b/drivers/staging/comedi/drivers/rtd520.c @@ -874,12 +874,10 @@ static int rtd_ai_cmdtest(struct comedi_device *dev, err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); - if (cmd->stop_src == TRIG_COUNT) { - /* TODO check for rounding error due to counter wrap */ - } else { - /* 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) return 3; -- 2.20.1