mesa: Don't call _mesa_ClipControl from glPopAttrib when unsupported.

Otherwise, calling glPopAttrib on drivers that don't support
ARB_clip_control gives you a GL error, which is surprising at best.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
i965: Update compaction code to handle Skylake like Cherryview.

Matt requested this in review feedback on the original patch, which I
completely missed when pushing this series.  Kristian also made this
change, but I grabbed the wrong version of the patch.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
i965: Add #defines for Broadwell HiZ workarounds in CACHE_MODE_1.

This patch adds macros needed for the HiZ PMA stall optimization.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
i965: Implement the PMA stall fix.

Certain non-promoted depth cases typically incur stalls.  In very
specific cases, we can enable a workaround which improves performance.

Improves performance in GLBenchmark 2.7 TRex by 1.17762% +/- 0.448765%
(n=75) at 1280x720 on Broadwell GT3.

Haswell has this feature as well, but we can't currently write registers
from userspace batches (and we'd incur additional software batch
scanning overhead as well), so we haven't enabled it.  Broadwell allows
us to write CACHE_MODE_1.  Backporters beware: the formula and flushing
incantation differs between Haswell and Broadwell.

v2: Move pma_stall_bits from brw->state to brw itself (requested by
    Kristian Høgsberg).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
i965: Re-enable Z16 on Gen8+.

Improves performance in GLBenchmark 2.7 TRex by 3.88889% +/- 0.336383%
(n=80) at 1280x720 on Broadwell GT3.  Together with the previous patch,
it improves performance by 5.42738% +/- 0.541971% (n=10) at 1920x1080.

Note that without the PMA stall fix, this would instead decrease
performance by 22%.

v2: Update comment (noticed by Kristian Høgsberg).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
ilo: add drm_configuration for the pipe-target

Allows the driver to advertise DMA-BUF and throttling.