Re: [RFC][PATCH 1/3] drm: drm_syncobj: Add note in DOC about absolute timeout values

From: John Stultz
Date: Tue Jul 12 2022 - 11:48:29 EST

On Tue, Jul 12, 2022 at 12:40 AM Christian König
<christian.koenig@xxxxxxx> wrote:
> Am 12.07.22 um 06:22 schrieb John Stultz:
> > After having to debug down through the kernel to figure out
> > why my _WAIT calls were always timing out, I realized its
> > an absolute timeout value instead of the more common relative
> > timeouts.
> >
> > This detail should be called out in the documentation, as while
> > the absolute value makes sense here, its not as common for timeout
> > values.
> Well absolute timeout values are mandatory for making -ERESTARTSYS work
> without any additional handling.

Yes! I'm not saying it's wrong to use absolute values, just that
relative values are common enough to create some confusion here.

> So using them is recommended for ~20 years now and IIRC even documented
> somewhere.

So in addition to "somewhere", why not in the interface documentation as well?

> See here as well how much trouble system
> calls with relative timeouts are.

Yep. Well aware. :)