On 23/03/16 16:50, Hartley Sweeten wrote:
On Wednesday, March 23, 2016 3:47 AM, Ian Abbott wrote:
On 22/03/16 17:01, H Hartley Sweeten wrote:
Step 4 of the (*do_cmdtest) calls dt282x_ns_to_timer() to work out the
divisor needed to generate the 'convert_arg' timing. If the 'convert_arg'
timing can not be generated, the function returns the max timing that can
be generated.
The Step 3 'max' check of the 'convert_arg' isn't necessary.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/dt282x.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index 06a87a1..be6a0bc 100644
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -689,8 +689,6 @@ static int dt282x_ai_cmdtest(struct comedi_device *dev,
err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 4000);
-#define SLOWEST_TIMER (250*(1<<15)*255)
- err |= comedi_check_trigger_arg_max(&cmd->convert_arg, SLOWEST_TIMER);
err |= comedi_check_trigger_arg_min(&cmd->convert_arg, board->ai_speed);
err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
cmd->chanlist_len);
I'd be inclined to keep the existing check in place, as it goes with the
arg_min test (although one of the arg_min tests on convert_arg is
redundant, as you point out in patch 2).
It's just unnecessary. And the #define in the function is a bit ugly in my opinion.
The upper and lower bounds on the timings are usually checked at step 3.
That's the case in amplc_pci230, cb_das16_cs, comedi_rt_timer,
dmm32at, dt2814, ni_pcidio, etc.
If it's removed the net effect is still the same. Only instead of the arg_max test
happening in the trivial validation (step 3) it will happen as a side effect of the
divisor calculation (step 4). If the user passes a convert_arg larger than
250*(1<<15)*255 (2,088,960,000 ns) it will still get changed to the acceptable
max value.
It could affect the number of test operations that need to be performed
on a particular command to get it to pass. For example, if convert_arg
is out of bounds and there is some other problem at step 3, but no other
problems at step 4, the old code would fail at step 3 and a subsequent
call would pass step 4, but the new code would fail at step 3 and a
subsequent call would also fail at step 4 (because convert_arg wasn't
adjusted by step 3).
But, if you prefer to keep it in I will modify this patch to just fix the
checkpatch.pl issue.
I prefer to keep the test for consistency, but you can make it less ugly
if you want.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Web: http://www.mev.co.uk/ )=-
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