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staging: comedi: dt282x: prevent "empty acquisition" async commands

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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 <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2014-09-09 16:15:48 -07:00 • committed by Greg Kroah-Hartman
commit 759658ddff
1 changed files with 6 additions and 8 deletions
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14
drivers/staging/comedi/drivers/dt282x.c
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@ -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;