[Intel-gfx] [PATCH 3/3] i965: check scratch page in a locked fashion on each ioctl

[Chris Wilson]

Quoting Rogovin, Kevin (2017-12-05 10:30:04)
> Hi,
> 
> > Per context, then you can remove the locking. It's fitting since the scratch page is per-context anyway.
> 
>  The scratch page is per context? This I did not know, I thought it was per PPGTT. If that is the case, then my proposed interface to get/set the scratch page contents is wrong because it does not pass the HW context id.

Yes, it per-vm, which is per-ctx on everything you want to investigate
on. gen4-7 it is a global GTT with a global scratch, and just a mutex
inside one process is not going to give you atomicity.
-Chris