[Intel-gfx] [PATCH] drm/i915: disable set/get_tiling ioctl on gen12+

[Daniel Vetter]

On Wed, Aug 28, 2019 at 08:31:27PM +0000, Souza, Jose wrote:
> On Wed, 2019-08-28 at 21:13 +0100, Chris Wilson wrote:
> > Quoting Souza, Jose (2019-08-28 21:11:53)
> > > Reviewed-by: José Roberto de Souza <jose.souza at intel.com>
> > 
> > It's using a non-standard for i915 error code, and get_tiling is not
> 
> Huum should it use ENOTSUPP then?!

https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#recommended-ioctl-return-values

Per above "feature not supported" -> EOPNOTSUPP.

> > affected, it will always return LINEAR. You cannot set tiling as 
> 
> Following this set_tiling() LINEAR should be allowed too.
> I prefer the current approach of returning error.

I'm not seeing the value in keeping get_tiling supported. Either userspace
still uses the legacy backhannel and dri2, in which case it needs to be
fixed no matter what. Or it's using modifiers, in which case this is dead
code. Only other user I can think of is takeover for fastboot, but if you
get anything else than untiled it's also broken (we don't have an ioctl to
read out the modifiers, heck even all the planes, there's no getfb2).

So really not seeing the point in keeping that working.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch