Re: [RFC][PATCH 1/3] drm: drm_syncobj: Add note in DOC about absolute timeout values
From: Christian König
Date: Tue Jul 12 2022 - 11:54:51 EST
Am 12.07.22 um 17:48 schrieb John Stultz:
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?
Because it's the desired default behavior and we shouldn't have to
document that on every instance it is used.
IIRC it's documented centralized (but I need to dig that up as well).
What we should do instead is to have a warning on every relative timeout
that this probably shouldn't be used as example.
Regards,+
Christian.
See here as well https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flwn.net%2FArticles%2F17744%2F&data=05%7C01%7Cchristian.koenig%40amd.com%7C68a13ac3906d4ac4cc4308da641df25c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637932377042931797%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=dM4BkqnO0LrsdKBwKKMvx4zMabWrM%2FY7pPGDsdFO%2BnI%3D&reserved=0 how much trouble system
calls with relative timeouts are.
Yep. Well aware. :)
thanks
-john