Re: [PATCH v5 1/5] Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation.

Dave Penkler
2015-11-28T17:41:39Z

On Sat, Nov 28, 2015 at 04:57:47PM +0200, Andy Shevchenko wrote:
> On Sat, Nov 28, 2015 at 1:55 PM, Dave Penkler <dpenkler@gmail.com> wrote:
> > On Wed, Nov 25, 2015 at 10:38:39PM +0200, Andy Shevchenko wrote:
> >> On Wed, Nov 25, 2015 at 11:18 AM, Dave Penkler <dpenkler@gmail.com> wrote:
> >> > On Sun, Nov 22, 2015 at 12:32:41PM +0200, Andy Shevchenko wrote:
> >> >> On Sun, Nov 22, 2015 at 11:19 AM, Dave Penkler <dpenkler@gmail.com> wrote:
> >> >> > On Wed, Nov 18, 2015 at 11:55:27AM +0200, Andy Shevchenko wrote:
> >> >> >> On Wed, Nov 18, 2015 at 10:37 AM, Dave Penkler <dpenkler@gmail.com> wrote:
>
> Thank you for an update!
>
> >> >> >> > + switch (status) {
> >> >> >> > + case 0: /* SUCCESS */
> >> >> >> > + if (data->iin_buffer[0] & 0x80) {
> >> >> >> > + /* check for valid STB notification */
> >> >> >> > + if ((data->iin_buffer[0] & 0x7f) > 1) {
>
> How can I miss that there are two conditionals in a sequence and
> moreover for the same data?!

Sorry, my fault, it is the combination of patch 1 and 2

> That might explain the optimization done by compiler.
>
> So, could it be transformed to simple one condition
> if (data->iin_buffer[0] > 0x81 /* 129 */) {
> ?

OK so now for patch 1 and 2 we have:

switch (status) {
case 0: /* SUCCESS */
/* PATCH 1 check for valid STB notification */
if (data->iin_buffer[0] > 0x81) {
data->bNotify1 = data->iin_buffer[0];
data->bNotify2 = data->iin_buffer[1];
atomic_set(&data->iin_data_valid, 1);
wake_up_interruptible(&data->waitq);
goto exit;
}
/* PATCH 2 check for SRQ notification */
if (data->iin_buffer[0] == 0x81) {
if (data->fasync)
kill_fasync(&data->fasync,
SIGIO, POLL_IN);

atomic_set(&data->srq_asserted, 1);
wake_up_interruptible(&data->waitq);
goto exit;
}

I'll push a new set if you are OK with this.
cheers,
-Dave