Re: [PATCH] pmdomain: qcom: rpmhpd: don't clamp gfx and gmxc before sync_state

[Vladyslav Tymoshchuk <tvlad744@gmail.com>]

On Wed, Oct 21, 2026 at 10:05:17AM +0200, Oleg Keri wrote:
> Until rpmhpd's sync_state every vote is clamped to the highest corner,
> so that hardware the bootloader left running keeps the rail level it
> needs until its driver takes over.  Nothing the bootloader leaves behind
> runs on the GPU rails, but the clamp hits them anyway: the GPU clock
> controller's probe runtime-resumes and suspends its GFX and GMXC
> domains, and from then on both rails are pinned at their highest corner
> until sync_state.

SM8750 (Adreno 830) is hit by the same clamp, with a different symptom
and without CLX, which is only enabled on X2-85 and A840 so far. The
first GPU init succeeds, but when the GMU first boots under the clamped
gfx vote, every ACD level runs at half the requested clock until the
next reboot. msm.disable_acd=1 avoids it.

OnePlus Pad 3, v7.3-rc5 plus board patches, msm as a module loaded by
udev about 4 s after boot, GMU firmware 5.1.25. The clock was measured
as drm-cycles-gpu over drm-engine-gpu in the fdinfo of a vkmark process
keeping the GPU busy, at fixed devfreq levels. The four kernels below
differ only in rpmhpd.c, and I alternated between them from boot to
boot. In every boot in the table the first GMU boot came 62-81 ms
before rpmhpd's sync_state:

  devfreq (MHz)            342   660   1050   1100
  without the patch        342   330    525    550   (10 boots)
  with the patch           342   660   1050   1100   (11 boots)
  local test, only gfx
  left out of the clamp    342   660   1050   1100   (5 boots)
  local test, only gmxc
  left out of the clamp    342   330    525    550   (5 boots)

Every value was the same within 1 MHz across the boots. On one boot of
each kernel I also went through all 14 OPPs. With gfx clamped, 525 MHz
and below ran at the requested clock, 607 MHz at 539-558 MHz, and
734 MHz and up at half. With gfx left out of the clamp, all 14 were
within 1 MHz of the requested clock.

In one more boot of the gmxc-only kernel, sync_state came 83 ms before
the first GMU boot, and that boot ran at the full clock. So, as on
Glymur, only gfx matters here, and only if the GMU first boots while
the clamp is still in place.

With vkmark's blur scene at a pinned 1100 MHz on the same boots, this
is 414-421 fps without the patch and 831-866 fps with it.

Tested-by: Vladyslav Tymoshchuk <tvlad744@gmail.com> # SM8750