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[v2,0/6] drm/panfrost: Turn off clocks and regulators in PM

Message ID 20231102142643.75288-1-angelogioacchino.delregno@collabora.com (mailing list archive)
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Series drm/panfrost: Turn off clocks and regulators in PM | expand

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AngeloGioacchino Del Regno Nov. 2, 2023, 2:26 p.m. UTC 
Changes in v2:
 - Added hard reset GPU recovery
 - Tightened polling time for soft reset and power on
 - New execution time measurements after poweroff fix (see [1])

[1]: https://lore.kernel.org/all/20231102141507.73481-1-angelogioacchino.delregno@collabora.com/

At least MediaTek platforms are able to get the GPU clocks and regulators
completely off during system suspend, allowing to save a bit of power.

Panfrost is used on more than just MediaTek SoCs and the benefits of this
can be variable across different SoC models and/or different SoCs from
different manufacturers: this means that just adding this ability for all
could result in unexpected issues and breakages on untested SoCs.

For the aforemenetioned reasons, turning off the clocks and/or regulators
was implemented inside of a capabilities barrier that shall be enabled on
a per-SoC basis (in the panfrost_compatible platform data) after testing
of both benefits and feasibility.

In this series, I am adding the ability to switch on/off clocks and
regulators and enabling that on all MediaTek platforms, as I was able
to successfully test that on multiple Chromebooks featuring different
MediaTek SoCs; specifically, I've manually tested on MT8186, MT8192 and
MT8195, while MT8183 got tested only by KernelCI.

Cheers!

AngeloGioacchino Del Regno (6):
  drm/panfrost: Perform hard reset to recover GPU if soft reset fails
  drm/panfrost: Tighten polling for soft reset and power on
  drm/panfrost: Implement ability to turn on/off GPU clocks in suspend
  drm/panfrost: Set clocks on/off during system sleep on MediaTek SoCs
  drm/panfrost: Implement ability to turn on/off regulators in suspend
  drm/panfrost: Set regulators on/off during system sleep on MediaTek
    SoCs

 drivers/gpu/drm/panfrost/panfrost_device.c | 78 ++++++++++++++++++++--
 drivers/gpu/drm/panfrost/panfrost_device.h | 13 ++++
 drivers/gpu/drm/panfrost/panfrost_drv.c    |  3 +
 drivers/gpu/drm/panfrost/panfrost_gpu.c    | 22 +++---
 drivers/gpu/drm/panfrost/panfrost_regs.h   |  1 +
 5 files changed, 105 insertions(+), 12 deletions(-)