Re: [PATCH 2/2] drm/i915: Fail addfb ioctl if color and CCS buffers overlap

Ville Syrjälä
2017-09-07T12:19:18Z

On Tue, Sep 05, 2017 at 08:36:54AM +0100, Daniel Stone wrote:
> Hi Ville,
>
> On 4 September 2017 at 17:37, Ville Syrjälä
> <ville.syrjala@linux.intel.com> wrote:
> > On Thu, Aug 31, 2017 at 04:52:15PM -0300, Gabriel Krisman Bertazi wrote:
> >> With this patch the new testcase igt@kms_ccs@pipe-X-invalid-ccs-offset
> >> succeeds.
> >
> > I don't think we actually want to reject overlap. I had a patch for that
> > years ago, but I decided to drop it because people might want to
> > interleave the planes in some interesting ways. Making the overlap
> > check accurate enough to allow that would be to total overkill. So IMO
> > it's perfectly fine to let the user shoot himself in the foot if they
> > mess up the offsets.
>
> Is that actually supported by any hardware renderer? If not, maybe the
> check should only be enabled for generations who support it.

Not sure I understand the question. You can program your offsets/strides
any which way you want,

--
Ville Syrjälä
Intel OTC