[Mesa-dev] [PATCH V6 10/27] i965: fix atomic buffer index for bindings other than 0

[Ilia Mirkin]

On Tue, Sep 29, 2015 at 2:48 AM, Timothy Arceri <t_arceri at yahoo.com.au> wrote:
> On Tue, 2015-09-29 at 02:33 -0400, Ilia Mirkin wrote:
>> On Tue, Sep 29, 2015 at 2:26 AM, Timothy Arceri <
>> t_arceri at yahoo.com.au> wrote:
>> > On Tue, 2015-09-29 at 02:08 -0400, Ilia Mirkin wrote:
>> > > On Tue, Sep 29, 2015 at 2:05 AM, Timothy Arceri <
>> > > t_arceri at yahoo.com.au> wrote:
>> > > > On Tue, 2015-09-29 at 01:05 -0400, Ilia Mirkin wrote:
>> > > No. I mean the line:
>> > >
>> > >       brw->vtbl.emit_buffer_surface_state(brw, &surf_offsets[i],
>> > > bo,
>> > >
>> > > Shouldn't that look up the atomic buffer index in prog->Uniforms
>> > > instead of using 'i'?
>> >
>> > No that looks fine. The problem in the patch was we didn't have the
>> > atomic buffex index and we used the binding as the offset which
>> > doesn't
>> > have to be the same as the buffer index.
>> >
>> > In brw_upload_abo_surfaces its the opposite we have the atomic
>> > buffer
>> > index which is i and we are looking up the binding to get the
>> > buffer
>> > object.
>> >
>> > Does that make sense?
>>
>> i is the binding index though...
>
> i is the buffer index
>
> See find_active_atomic_counters() for the code the counts the active
> buffers.
>
> http://cgit.freedesktop.org/mesa/mesa/tree/src/glsl/link_atomics.cpp#n9
> 9
>
> This count is then used to set NumAtomicBuffers and to create the prog
> ->AtomicBuffers array so the array is no bigger than it needs to be.
> This is the reason the binding and atomic buffer index can differ.
>
> http://cgit.freedesktop.org/mesa/mesa/tree/src/glsl/link_atomics.cpp#n1
> 73

Do you agree that NumAtomicBuffers can go up to
MaxCombinedAtomicBuffers? If so, that's problematic, when it's >
MaxAtomicBuffers, right?

  -ilia