[Intel-gfx] [PATCH v4 2/2] drm/i915: Create dumb buffer from LMEM

[Ramalingam C]

On 2019-12-05 at 13:11:29 +0000, Chris Wilson wrote:
> Quoting Ramalingam C (2019-12-05 13:02:40)
> > On 2019-12-05 at 12:20:12 +0000, Chris Wilson wrote:
> > > Quoting Matthew Auld (2019-12-05 12:12:19)
> > > > We would still need to clear the object(maybe I915_BO_ALLOC_CLEARED?)
> > > > in order to pass the IGTs. We also need to adjust dumb_buffer.c, since
> > > > that uses get_avail_ram_mb() for always_clear, but maybe we need the
> > > > query region uapi for that?
> > > 
> > > Hmm. Questions over the maximum size for dumb buffer, maximum number of
> > > dumb buffers, etc, should be addressed to the dumb API. So some form of
> > > drmGetCap() ?
> > Chris, Is this suggestion to add this capability probing through a new IOCTL for
> > dumb APIs? Please clarify.
> 
> I don't think we need a new ioctl, as drm_getcap already covers the dumb
> buffer API. We just need to expose the limits of the dumb buffer API
> through it.
> 
> The 2 that spring to mind are maximum size of individual buffer and
> maximum size of total dumb buffers.

Will there be question for userspace for this extension or no?
AFAIK There is no consumer except IGT.

-Ram

> (The latter may be infinite for
> drivers that allow swapping of inactive buffers.) There was a request on
> irc for something like this as well, but I'm not aware of the context.
> -Chris