[Mesa-dev] [PATCH] r600g: remove one pointless flush

[Marek Olšák]

On Fri, Oct 28, 2011 at 10:52 PM, Vadim Girlin <vadimgirlin at gmail.com> wrote:
> On Fri, 2011-10-28 at 19:47 +0200, Marek Olšák wrote:
>> I've got no idea what the flush was good for, but it's useless from
>> the looks of it. The rest of the patch is just a cleanup resulting
>> from some of the variables being no longer used for anything useful.
>>
>> There are no piglit regressions.
>
> It was intended to handle multiple interleaved query and conditional
> render calls with single query object (in this case in theory we may
> have multiple outstanding queries in current CS and separate data block
> in the buffer for each query, with possible buffer overflow). I wasn't

Do you mean this?

while (1) {
  begin_query(q);
  draw();
  end_query(q);
  render_condition(q);
  draw();
  render_condition(NULL);
}

begin_query always resets query results to 0 anyway, so in theory, we
could re-use the same data block over and over again. I think the only
case where buffer overflow may happen is:

begin_query(q);
while (1) {
  draw();
  suspend_queries(); // flush or u_blitter
  resume_queries();
}
end_query(q);

Correct?

Marek