[Mesa-dev] [PATCH] anv/cmd_buffer: check for NULL framebuffer

[Jason Ekstrand]

On Mon, Feb 4, 2019 at 3:02 AM Juan A. Suarez Romero <jasuarez at igalia.com>
wrote:

> On Fri, 2019-02-01 at 15:33 -0600, Jason Ekstrand wrote:
> > On Fri, Feb 1, 2019 at 10:14 AM Juan A. Suarez Romero <
> jasuarez at igalia.com> wrote:
> > > This can happen when we record a VkCmdDraw in a secondary buffer that
> > > was created inheriting from the primary buffer, but with the
> framebuffer
> > > set to NULL in the VkCommandBufferInheritanceInfo.
> > >
> > > CC: Jason Ekstrand <jason at jlekstrand.net>
> > > ---
> > >  src/intel/vulkan/gen7_cmd_buffer.c | 13 +++++++++++--
> > >  1 file changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/src/intel/vulkan/gen7_cmd_buffer.c
> b/src/intel/vulkan/gen7_cmd_buffer.c
> > > index 352892aee33..fe1a47f6ce6 100644
> > > --- a/src/intel/vulkan/gen7_cmd_buffer.c
> > > +++ b/src/intel/vulkan/gen7_cmd_buffer.c
> > > @@ -70,12 +70,21 @@ gen7_cmd_buffer_emit_scissor(struct anv_cmd_buffer
> *cmd_buffer)
> > >        };
> > >
> > >        const int max = 0xffff;
> > > +
> > > +      uint32_t height = 0;
> > > +      uint32_t width = 0;
> > > +
> > > +      if (fb) {
> > > +        height = fb->height;
> > > +        width = fb->width;
> > > +      }
> > > +
> > >        struct GEN7_SCISSOR_RECT scissor = {
> > >           /* Do this math using int64_t so overflow gets clamped
> correctly. */
> > >           .ScissorRectangleYMin = clamp_int64(s->offset.y, 0, max),
> > >           .ScissorRectangleXMin = clamp_int64(s->offset.x, 0, max),
> > > -         .ScissorRectangleYMax = clamp_int64((uint64_t) s->offset.y +
> s->extent.height - 1, 0, fb->height - 1),
> > > -         .ScissorRectangleXMax = clamp_int64((uint64_t) s->offset.x +
> s->extent.width - 1, 0, fb->width - 1)
> > > +         .ScissorRectangleYMax = clamp_int64((uint64_t) s->offset.y +
> s->extent.height - 1, 0, height - 1),
> > > +         .ScissorRectangleXMax = clamp_int64((uint64_t) s->offset.x +
> s->extent.width - 1, 0, width - 1)
> >
> > If fb == NULL, won't width/height be 0 and this be -1 and we end up
> clamping to -1?  I think we want to rather make the clamp conditional on
> having the framebuffer.
> >
>
> Right. And as ScissorRectangle(X/Y)Max is an uint value, its value would be
> MAX_UINT.
>

Which is fine if they specified a scissor that is >= the framebuffer size.
However, if they are actually trying to scissor something, this makes their
scissor disappear.  That's bad. :-)

--Jason


> I think as we do not know the framebuffer size (which will be know later,
> IIUC),
> we are emitting the scissor for the full rectangle.
>
>
>
>
> > --Jason
> >
> > >        };
> > >
> > >        if (s->extent.width <= 0 || s->extent.height <= 0) {
>
>
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