Commit 8c602c49 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

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

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

Signed-off-by: default avatarH Hartley Sweeten <>
Reviewed-by: default avatarIan Abbott <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 1e2e39ef
......@@ -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 {
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;
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