[igt-dev] [PATCH i-g-t v2] tests/dumb_buffer: Tests for creation

[Chris Wilson]

Quoting Ramalingam C (2019-11-28 12:19:22)
> On 2019-11-28 at 11:44:04 +0000, Chris Wilson wrote:
> > Quoting Ramalingam C (2019-11-28 11:35:36)
> > > On 2019-11-28 at 16:57:33 +0530, Ramalingam C wrote:
> > > > Tests are developed for dumb buffer creation.
> > > > 
> > > > v2:
> > > >   Made as a generic test for dumb buffer creation [Chris]
> > > Chris,
> > > 
> > > As you have mentioned I have made this as generic test.
> > 
> > We have a different idea about generic :)
> > 
> > gem_write/gem_read are i915 ioctls.
> > 
> > We want to only use DUMB_CREATE, DUMB_MMAP, DUMB_DESTROY and then it
> > will work with DRIVER_ANY.
> Except DUMP_MMAP used all other stuff... missed that gem_read is using
> DRM_IOCTL_I915_GEM_PREAD. I tried with dumb_mmap + mem_cpy instead of gem_read. But failed there for unknown reasons.

Hmm. We don't need a DUMB_SYNC as a dumb buffer should never be accessed
by anything other than DUMB_MMAP (no GPU rendering) and scanout (read
from HW, never write). So GPU coherency issues are outside the scope of
the dumb api, but if you can find stale data just by using DUMB_MMAP we
need to fix that pronto.
-Chris