[PATCH v2 0/5] Power Management for Raspberry Pi V3D GPU

Maíra Canal
2025-07-31T21:06:45Z

This series introduces Runtime PM for Raspberry Pi's GPU, V3D.
Currently, the GPU clock stays up during the whole operation, even if
the GPU is idle. By introducing Runtime PM, we can now turn off the
clock completely during idle. For example, with this series, when
checking `vcgencmd measure_clock v3d` in the Raspberry Pi 5, we get:

(idle)

$ vcgencmd measure_clock v3d
frequency(0)=0

(running glmark2)

$ vcgencmd measure_clock v3d
frequency(0)=960016128

To implement PM for V3D, it was needed to add a prepare and unprepare
hook to RPi's firmware clocks. Currently, they don't turn on and off,
nor lower the clock rate. Therefore, PATCH 2/5 addresses this issue in
clk/bcm/clk-raspberrypi.c.

Apart from the first patch, the last three patches are related to PM
enablement in the V3D driver.

To ease testing in Raspberry Pi 4 and 5, I prepared a downstream branch
backporting this series to rpi-6.12.y [1].

[1] https://github.com/mairacanal/linux-rpi/tree/v3d/downstream/power-management-v2

Best Regards,
- Maíra

---
v1 -> v2: https://lore.kernel.org/r/20250728-v3d-power-management-v1-0-780f922b1048@igalia.com

- [1/5] NEW PATCH: "clk: bcm: rpi: Add missing logs if firmware fails" (Stefan Wahren)
- [2/5] Remove the "Fixes:" tag (Stefan Wahren)
- [2/5] dev_err_ratelimited() instead of dev_err() (Stefan Wahren)
- [2/5] Instead of logging the clock ID, use clk_hw_get_name(hw) to log the name (Stefan Wahren)
- [2/5] Add a newline character at the end of the log message (Stefan Wahren)
- [2/5] Use CLK_IS_CRITICAL for all clocks that can't be disabled (Maxime Ripard)
- [3/5] NEW PATCH: "clk: bcm: rpi: Maximize V3D clock"
- [4/5] Use devm_reset_control_get_optional_exclusive() (Philipp Zabel)
- [4/5] Make sure that resource are cleaned in the inverse order of allocation (Philipp Zabel)

---
Maíra Canal (4):
clk: bcm: rpi: Turn firmware clock on/off when preparing/unpreparing
clk: bcm: rpi: Maximize V3D clock
drm/v3d: Allocate all resources before enabling the clock
drm/v3d: Introduce Runtime Power Management

Stefan Wahren (1):
clk: bcm: rpi: Add missing logs if firmware fails

drivers/clk/bcm/clk-raspberrypi.c | 72 ++++++++++++++++-
drivers/gpu/drm/v3d/Makefile | 3 +-
drivers/gpu/drm/v3d/v3d_debugfs.c | 23 +++++-
drivers/gpu/drm/v3d/v3d_drv.c | 160 ++++++++++++++++++--------------------
drivers/gpu/drm/v3d/v3d_drv.h | 21 ++++-
drivers/gpu/drm/v3d/v3d_gem.c | 18 ++++-
drivers/gpu/drm/v3d/v3d_irq.c | 15 ++--
drivers/gpu/drm/v3d/v3d_mmu.c | 12 ++-
drivers/gpu/drm/v3d/v3d_power.c | 79 +++++++++++++++++++
drivers/gpu/drm/v3d/v3d_submit.c | 19 ++++-
10 files changed, 311 insertions(+), 111 deletions(-)
---
base-commit: 518867b09394217d13f6e05f704450bd9d2c8eeb
change-id: 20250728-v3d-power-management-eebb2024dc96