> -----Original Message-----
> From: Andrew Lunn <[email protected]>
> Sent: Thursday, February 19, 2026 9:25 AM
> To: Shenwei Wang <[email protected]>
> Cc: Arnaud POULIQUEN <[email protected]>; Linus Walleij
> <[email protected]>; Bartosz Golaszewski <[email protected]>; Jonathan Corbet
> <[email protected]>; Rob Herring <[email protected]>; Krzysztof Kozlowski
> <[email protected]>; Conor Dooley <[email protected]>; Bjorn Andersson
> <[email protected]>; Mathieu Poirier <[email protected]>; Frank Li
> <[email protected]>; Sascha Hauer <[email protected]>; Shuah Khan
> <[email protected]>; [email protected]; linux-
> [email protected]; [email protected]; Pengutronix Kernel Team
> <[email protected]>; Fabio Estevam <[email protected]>; Peng Fan
> <[email protected]>; [email protected]; linux-
> [email protected]; [email protected]; linux-arm-
> [email protected]; dl-linux-imx <[email protected]>; Bartosz
> Golaszewski <[email protected]>
> Subject: [EXT] Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg GPIO driver
> On Thu, Feb 19, 2026 at 02:17:26PM +0000, Shenwei Wang wrote:
> >
> >
> > > -----Original Message-----
> > > From: Andrew Lunn <[email protected]>
> > > Sent: Thursday, February 19, 2026 7:27 AM
> > > To: Arnaud POULIQUEN <[email protected]>
> > > Cc: Shenwei Wang <[email protected]>; Linus Walleij
> > > <[email protected]>; Bartosz Golaszewski <[email protected]>; Jonathan
> > > Corbet <[email protected]>; Rob Herring <[email protected]>; Krzysztof
> > > Kozlowski <[email protected]>; Conor Dooley <[email protected]>;
> > > Bjorn Andersson <[email protected]>; Mathieu Poirier
> > > <[email protected]>; Frank Li <[email protected]>; Sascha
> > > Hauer <[email protected]>; Shuah Khan
> > > <[email protected]>; [email protected]; linux-
> > > [email protected]; [email protected]; Pengutronix
> > > Kernel Team <[email protected]>; Fabio Estevam
> > > <[email protected]>; Peng Fan <[email protected]>;
> > > [email protected]; linux- [email protected];
> > > [email protected]; linux-arm- [email protected];
> > > dl-linux-imx <[email protected]>; Bartosz Golaszewski
> > > <[email protected]>
> > > Subject: [EXT] Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg
> > > GPIO driver
> > >
> > > > > + if (sync) {
> > > > > + err = wait_for_completion_timeout(&info->cmd_complete,
> > > > > +
> > > > > msecs_to_jiffies(RPMSG_TIMEOUT));
> > > > > + if (err == 0) {
> > > > > + dev_err(&info->rpdev->dev, "rpmsg_send
> > > > > timeout!\n");
> > > > > + return -ETIMEDOUT;
> > > >
> > > > strange condition you return an error if err == 0, for redability use
> > > > 'ret'
> > > > variable or simply:
> > > >
> > > > if(!wait_for_completion_timeout(&info->cmd_complete,
> > > > msecs_to_jiffies(RPMSG_TIMEOUT)) {
> > > > dev_err(&info->rpdev->dev, "rpmsg_send
> > > > timeout!\n");
> > > > return -ETIMEDOUT;
> > > > }
> > >
> > > This will be from a comment i made. It appears that
> > > do_wait_for_common() can return -ERESTARTSYS. I assume that should
> > > be returned to user space?
> > >
> >
> > It looks like there might be a bit of confusion around what
> > wait_for_completion_timeout() actually returns. That function never
> > returns -ERESTARTSYS. Instead, its behavior is pretty
> > simple:
> >
> > - 0 means the wait timed out
> > - A positive value means the completion happened (the value is just
> > the remaining jiffies)
> >
> > So the driver returns the timeout error, and the upper application can
> > decide how it wants to handle that situation, for example restart or ignore.
>
> wait_for_completion_timeout():
> return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
>
> wait_for_common():
> return __wait_for_common(x, io_schedule_timeout, timeout, state);
>
> __wait_for_common():
> timeout = do_wait_for_common(x, action, timeout, state);
> ...
> return timeout;
>
> do_wait_for_common():
>
> do {
> if (signal_pending_state(state, current)) {
> timeout = -ERESTARTSYS;
Once wait_for_common() is called with state = TASK_UNINTERRUPTIBLE,
signal_pending_state() will
always return false. As a result, -ERESTARTSYS is not a possible return value
in this scenario.
Thanks,
Shenwei
> break;
> }
> ...
> } while (!x->done && timeout); ...
> if (!x->done)
> return timeout;
> ...
> return timeout ?: 1;
> Andrew
