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

[Dmitry Osipenko]

09.09.2020 11:26, Mikko Perttunen пишет:
> On 9/9/20 4:24 AM, Dmitry Osipenko wrote:
>> 09.09.2020 04:13, Dmitry Osipenko пишет:
>> ...
>>> How many sync points would use an average job? Maybe it should be better
>>> to have the predefined array of sync points within the struct
>>> drm_tegra_channel_submit?
>>>
>>
>> The same question regarding the commands.
>>
>> Wouldn't it be a good idea to make both usrptr arrays of sync points and
>> commands optional by having a small fixed-size buffers within
>> drm_tegra_channel_submit? Then a majority of jobs would only need to
>> copy the gather data from userspace.
>>
> 
> Sure, I'll look into it. For syncpoints, it would be usually 1 but
> sometimes 2, so maybe make it 2. For commands, at least for downstream
> it would typically be 2 (one wait and one gather). Any opinion from
> grate-driver's point of view? Not sure if there is any recommendation
> regarding the max size of IOCTL data.

The Opentegra will need more than 2 commands. We'll need to take a look
at what are the min/max/average numbers of commands are used by
Opentegra since it combines multiple jobs into one and each job may have
several wait commands.