From 759658ddff327675bbf35063e2b04e0d7424124d Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 9 Sep 2014 16:15:48 -0700 Subject: [PATCH] staging: comedi: dt282x: prevent "empty acquisition" async commands This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg of 0 for both the analog input and output async commands. The (*do_cmd) for both subdevices sets up and starts the command without handling the "empty acquisition". This results in the interrupt functions 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/dt282x.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c index e725e3bf1532..cc974a5e5cf6 100644 --- a/drivers/staging/comedi/drivers/dt282x.c +++ b/drivers/staging/comedi/drivers/dt282x.c @@ -728,11 +728,10 @@ static int dt282x_ai_cmdtest(struct comedi_device *dev, err |= cfc_check_trigger_arg_min(&cmd->convert_arg, board->ai_speed); err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); - if (cmd->stop_src == TRIG_COUNT) { - /* any count is allowed */ - } else { /* TRIG_NONE */ + if (cmd->stop_src == TRIG_COUNT) + err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1); + else /* TRIG_EXT | TRIG_NONE */ err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0); - } if (err) return 3; @@ -890,11 +889,10 @@ static int dt282x_ao_cmdtest(struct comedi_device *dev, err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0); err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len); - if (cmd->stop_src == TRIG_COUNT) { - /* any count is allowed */ - } else { /* TRIG_NONE */ + if (cmd->stop_src == TRIG_COUNT) + err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1); + else /* TRIG_EXT | TRIG_NONE */ err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0); - } if (err) return 3; -- 2.20.1