[RFC PATCH v2 17/17] WIP: drm/tegra: Implement new UAPI

[Dmitry Osipenko]

09.09.2020 11:36, Mikko Perttunen пишет:
...
>>
>> Does it make sense to have timeout in microseconds?
>>
> 
> Not sure, but better have it a bit more fine-grained rather than
> coarse-grained. This still gives a maximum timeout of 71 minutes so I
> don't think it has any negatives compared to milliseconds.

If there is no good reason to use microseconds right now, then should be
better to default to milliseconds, IMO. It shouldn't be a problem to
extend the IOCLT with a microseconds entry, if ever be needed.

{
	__u32 timeout_ms;
...
	__u32 timeout_us;
}

timeout = timeout_ms + 1000 * timeout_us;

There shouldn't be a need for a long timeouts, since a job that takes
over 100ms is probably too unpractical. It also should be possible to
detect a progressing job and then defer timeout in the driver. At least
this is what other drivers do, like etnaviv driver for example:

https://elixir.bootlin.com/linux/v5.9-rc4/source/drivers/gpu/drm/etnaviv/etnaviv_sched.c#L107