[PATCH v7 1/5] clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks

Tue Mar 31 05:49:24 PDT 2026

On Thu, Mar 12, 2026 at 06:34:23PM -0300, Maíra Canal wrote:

> On current firmware versions, RPI_FIRMWARE_SET_CLOCK_STATE doesn't
> actually power off the clock. To achieve meaningful power savings, the
> clock rate must be set to the minimum before disabling. This might be
> fixed in future firmware releases.

> Rather than pushing rate management to clock consumers, handle it
> directly in the clock framework's prepare/unprepare callbacks. In
> unprepare, set the rate to the minimum before disabling the clock.
> In prepare, for clocks marked with `maximize` (currently v3d),
> restore the rate to the maximum after enabling.

I'm seeing boot regressions in -next with NFS root on Raspberry Pi 3B+
which bisect to this commit.  We get a likely unrelated oops from the
firmware interface and the boot grinds to a halt some time later since
the ethernet never comes up:

[   21.898686] Firmware transaction 0x00030066 timeout
[   21.898769] WARNING: drivers/firmware/raspberrypi.c:128 at rpi_firmware_property_list+0x200/0x280, CPU#2: (udev-worker)/115

...

[   22.067074] Call trace:
[   22.069538]  rpi_firmware_property_list+0x200/0x280 (P)
[   22.074824]  rpi_firmware_property+0x70/0xb8
[   22.079140]  vc4_drm_bind+0x12c/0x354 [vc4]
[   22.083368]  try_to_bring_up_aggregate_device+0x16c/0x1e0
[   22.088831]  component_master_add_with_match+0xb0/0xec
[   22.094027]  vc4_platform_drm_probe+0xc0/0xfc [vc4]
[   22.098961]  platform_probe+0x5c/0xa4

[0;1;31mTimed out while waiting for udev queue to empty.[0m
Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/nfs-top ... done.
Begin: Running /scripts/nfs-premount ... Waiting up to 60 secs for any ethernet to become available

Full log:
   https://lava.sirena.org.uk/scheduler/job/2617478#L1124

bisect log:

# bad: [cf7c3c02fdd0dfccf4d6611714273dcb538af2cb] Add linux-next specific files for 20260330
# good: [a010730e610019b6d010ec43ce737cb59a37809d] Merge branch 'for-linux-next-fixes' of https://gitlab.freedesktop.org/drm/misc/kernel.git
# good: [3398da5432899c09712f30c92a154f3bf760a3e7] Merge branch 'clk-renesas' into clk-next
# good: [777bc3284f0360c66ac75a44f35fc96053536ca4] Merge branch 'clk-cleanup' into clk-next
# good: [f520a492e07bc6718e26cfb7543ab4cadd8bb0e2] clk: xgene: Fix mapping leak in xgene_pllclk_init()
# good: [aeb078cebc40d421f61a8f07b0e7919aeb44d751] arm64: dts: broadcom: bcm2712-d-rpi-5-b: add fixes for pinctrl/pinctrl_aon
# good: [9be71d462c33b1a00acfa4ab8f0f5332ed592817] firmware: cs_dsp: Simplify suppressing log messages during KUnit testing
# good: [7b3f8db159f710d432c4edc024fcefa9e62e8b4b] ASoC: fsl_xcvr: add bitcount and timestamp controls
# good: [8fc5c7895185d1119ae76b509892a1d14e0bd483] ASoC: wm_adsp: Combine some similar code in firmware file search
# good: [981b080a79724738882b0af1c5bb7ade30d94f24] spi: fsl-qspi: Use reinit_completion() for repeated operations
# good: [ed0313223ce6514dbd39c049e25f702980d7e3cc] ASoC: codecs: wcd9335: Remove potential undefined behavior in wcd9335_slimbus_irq()
# good: [97af961568c8682c44506c9ad4b26c8a5455ec1d] ASoC: cs35l56: Put OTP register defines in correct address order
# good: [0a208adefecb287d22321054470d4619cb303839] ASoC: cs42l43: Add support for the B variant
# good: [a8075ada4a341ce58ebf8bef0188cefe6c2f6487] ASoC: ti: davinci-mcasp: improve aux_div selection for mid-range dividers
# good: [82169065ffb07577075a5088b313d78673ded331] memory: tegra: Add MC error logging support for Tegra264
# good: [aa3d0c93a333182e887426366a4f3e5f06ee0d83] regulator: max20411: show failure on register
# good: [ef0b4783afc211a4b120e72b5a57f3d0340a9981] ASoC: cs35l56: KUnit tests for reading speaker ID from host GPIOs
# good: [e7662bced2e98ffa2c572126677deb9cf55d43b3] regcache: Move HW readback after cache initialisation
# good: [b1ef855c62601ed4de2c4b0ff75a075877e3dac8] regmap: Simplify devres handling
# good: [96f06d055ca03d1dfb5830fd07ff6eadbd66264c] spi: dt-bindings: mpfs-spi: remove clock-names
# good: [2adac914c72b6cb5aba2612f49050c82aecd498e] ASoC: cs35l56-test: Add test cases without onchip pulls defined
# good: [f48e7a246a567e3764112e2463274c479d95cd96] ASoC: soc-core: Use guard()/scoped_guard() for mutex lock
# good: [9891b52ba12e9d5fed5901b6b5f6e0cdcd424390] regcache: Factor out regcache_hw_exit() helper
# good: [e84141846decb77d2826e553318a608b256804e5] regulator: pf9453: Allow shared IRQ
# good: [9ab637ac5d3826606947f4e861107da958eda324] regcache: Amend printf() specifiers when printing registers
# good: [34b4fc44e4f904fbb81335d53163ffdcb0180000] ASoC: soc_sdw_utils: remove index from sdca codec name
# good: [1696fad8b259a2d46e51cd6e17e4bcdbe02279fa] ASoC: sti: use managed regmap_field allocations
# good: [d3b693a13b39bce16e284e1c737874966b3a96de] spi: spi-mem: clean up kernel-doc in spi-mem.h
# good: [06dba254de95b16e7793224d29daa5195de2e581] ASoC: dt-bindings: nvidia,tegra-audio-max9808x: document additional board pins
# good: [17c6bf433742e0c1ff5ce175145877c0194e4a7a] ASoC: cs35l45: Hibernate wm_adsp on runtime suspend
# good: [da37bfe76b5b4ccc01ed8132215098e20d78e5f3] ASoC: cs42xx8: add error checks for constraints in TDM mode
# good: [501efdcb3b3ab099fc0ce2f6e668b1c4095dd476] ASoC: SDCA: Pull the Q7.8 volume helpers out of soc-ops
# good: [2974aa42e6696a1d95b727d677dc01a71af5b998] ASoC: remove snd_soc_pcm_subclass
# good: [d90c0f78379454d51a428e312ac6db573060185c] regulator: cpcap-regulator: add support for Mot regulators
# good: [5c74a008ffc62fc57a041602b4517519c8bf9436] firmware: cs_dsp: Mark KUnit test suites KUNIT_SPEED_SLOW
# good: [260c3fff1fefc570d8f23e87953e181d7d248861] ASoC: cs-amp-lib-test: Stop including platform_device.h
# good: [7c12f6ead4672cb08b74e6f6115eb04dca8ccfa4] spi: tegra210-quad: Add runtime autosuspend support
# good: [37983fad7f3ef296fa0504c8e945987459dc5487] regmap: define cleanup helper for regmap_field
# good: [ada32396f90951e12465224c04742607ca56a982] ASoC: SDCA: Add CS47L47 to class driver
# good: [e02902dd493bf9c9b05353c761737ac514ad7a5c] spi: add devm_spi_new_ancillary_device()
# good: [507a071d9868cb60e4e76f8a06fc8eb014f59ae4] spi: pxa2xx: use min() instead of min_t()
# good: [fed6e5084894373d76270cad4a32eb6479ad8247] spi: atcspi200: Remove redundant assignment to .owner
# good: [5ebc20921b7fff9feb44de465448e17a382c9965] ASoC: tas2552: Allow audio enable GPIO to sleep
# good: [171b3663f33e1efdc97f5112f49be10b47b20fa8] ASoC: codecs: aw88261: Add firmware-name support
# good: [c2bcf62ca75c541ec4297e6ff02a68ddc2e02029] regcache: Split regcache_count_cacheable_registers() helper
# good: [0556bb42a84ee391a2145ddba86756f9747bc27f] regulator: pf0900: Make regu_irqs variable static const
# good: [d075cef4af6327a5de4bee7bf77591e3201e54f4] ASoC: simple-card-utils: add sysclk ordering support
# good: [78dfbd4ad0be9f51de7b9a19388809254aeccd26] ASoC: Add quirk for Lecoo Bellator N176
# good: [bf122191473e26a8f195308b1ba924c98424c8e1] ASoC: rt5677-spi: Add SPI device ID matching table
# good: [fbb4c52ccdcb4a612d2b7f800aa57090eeee16d7] regulator: spacemit-p1: Update supply names
git bisect start 'cf7c3c02fdd0dfccf4d6611714273dcb538af2cb' 'a010730e610019b6d010ec43ce737cb59a37809d' '3398da5432899c09712f30c92a154f3bf760a3e7' '777bc3284f0360c66ac75a44f35fc96053536ca4' 'f520a492e07bc6718e26cfb7543ab4cadd8bb0e2' 'aeb078cebc40d421f61a8f07b0e7919aeb44d751' '9be71d462c33b1a00acfa4ab8f0f5332ed592817' '7b3f8db159f710d432c4edc024fcefa9e62e8b4b' '8fc5c7895185d1119ae76b509892a1d14e0bd483' '981b080a79724738882b0af1c5bb7ade30d94f24' 'ed0313223ce6514dbd39c049e25f702980d7e3cc' '97af961568c8682c44506c9ad4b26c8a5455ec1d' '0a208adefecb287d22321054470d4619cb303839' 'a8075ada4a341ce58ebf8bef0188cefe6c2f6487' '82169065ffb07577075a5088b313d78673ded331' 'aa3d0c93a333182e887426366a4f3e5f06ee0d83' 'ef0b4783afc211a4b120e72b5a57f3d0340a9981' 'e7662bced2e98ffa2c572126677deb9cf55d43b3' 'b1ef855c62601ed4de2c4b0ff75a075877e3dac8' '96f06d055ca03d1dfb5830fd07ff6eadbd66264c' '2adac914c72b6cb5aba2612f49050c82aecd498e' 'f48e7a246a567e3764112e2463274c479d95cd96' '9891b52ba12e9d5fed5901b6b5f6e0cdcd424390' 'e84141846decb77d2826e553318a608b256804e5' '9ab637ac5d3826606947f4e861107da958eda324' '34b4fc44e4f904fbb81335d53163ffdcb0180000' '1696fad8b259a2d46e51cd6e17e4bcdbe02279fa' 'd3b693a13b39bce16e284e1c737874966b3a96de' '06dba254de95b16e7793224d29daa5195de2e581' '17c6bf433742e0c1ff5ce175145877c0194e4a7a' 'da37bfe76b5b4ccc01ed8132215098e20d78e5f3' '501efdcb3b3ab099fc0ce2f6e668b1c4095dd476' '2974aa42e6696a1d95b727d677dc01a71af5b998' 'd90c0f78379454d51a428e312ac6db573060185c' '5c74a008ffc62fc57a041602b4517519c8bf9436' '260c3fff1fefc570d8f23e87953e181d7d248861' '7c12f6ead4672cb08b74e6f6115eb04dca8ccfa4' '37983fad7f3ef296fa0504c8e945987459dc5487' 'ada32396f90951e12465224c04742607ca56a982' 'e02902dd493bf9c9b05353c761737ac514ad7a5c' '507a071d9868cb60e4e76f8a06fc8eb014f59ae4' 'fed6e5084894373d76270cad4a32eb6479ad8247' '5ebc20921b7fff9feb44de465448e17a382c9965' '171b3663f33e1efdc97f5112f49be10b47b20fa8' 'c2bcf62ca75c541ec4297e6ff02a68ddc2e02029' '0556bb42a84ee391a2145ddba86756f9747bc27f' 'd075cef4af6327a5de4bee7bf77591e3201e54f4' '78dfbd4ad0be9f51de7b9a19388809254aeccd26' 'bf122191473e26a8f195308b1ba924c98424c8e1' 'fbb4c52ccdcb4a612d2b7f800aa57090eeee16d7'
# test job: [3398da5432899c09712f30c92a154f3bf760a3e7] https://lava.sirena.org.uk/scheduler/job/2608225
# test job: [777bc3284f0360c66ac75a44f35fc96053536ca4] https://lava.sirena.org.uk/scheduler/job/2608418
# test job: [f520a492e07bc6718e26cfb7543ab4cadd8bb0e2] https://lava.sirena.org.uk/scheduler/job/2608110
# test job: [aeb078cebc40d421f61a8f07b0e7919aeb44d751] https://lava.sirena.org.uk/scheduler/job/2579214
# test job: [9be71d462c33b1a00acfa4ab8f0f5332ed592817] https://lava.sirena.org.uk/scheduler/job/2548706
# test job: [7b3f8db159f710d432c4edc024fcefa9e62e8b4b] https://lava.sirena.org.uk/scheduler/job/2548248
# test job: [8fc5c7895185d1119ae76b509892a1d14e0bd483] https://lava.sirena.org.uk/scheduler/job/2548893
# test job: [981b080a79724738882b0af1c5bb7ade30d94f24] https://lava.sirena.org.uk/scheduler/job/2545092
# test job: [ed0313223ce6514dbd39c049e25f702980d7e3cc] https://lava.sirena.org.uk/scheduler/job/2544887
# test job: [97af961568c8682c44506c9ad4b26c8a5455ec1d] https://lava.sirena.org.uk/scheduler/job/2543911
# test job: [0a208adefecb287d22321054470d4619cb303839] https://lava.sirena.org.uk/scheduler/job/2542875
# test job: [a8075ada4a341ce58ebf8bef0188cefe6c2f6487] https://lava.sirena.org.uk/scheduler/job/2540933
# test job: [82169065ffb07577075a5088b313d78673ded331] https://lava.sirena.org.uk/scheduler/job/2582197
# test job: [aa3d0c93a333182e887426366a4f3e5f06ee0d83] https://lava.sirena.org.uk/scheduler/job/2531504
# test job: [ef0b4783afc211a4b120e72b5a57f3d0340a9981] https://lava.sirena.org.uk/scheduler/job/2530821
# test job: [e7662bced2e98ffa2c572126677deb9cf55d43b3] https://lava.sirena.org.uk/scheduler/job/2530804
# test job: [b1ef855c62601ed4de2c4b0ff75a075877e3dac8] https://lava.sirena.org.uk/scheduler/job/2531890
# test job: [96f06d055ca03d1dfb5830fd07ff6eadbd66264c] https://lava.sirena.org.uk/scheduler/job/2523404
# test job: [2adac914c72b6cb5aba2612f49050c82aecd498e] https://lava.sirena.org.uk/scheduler/job/2523920
# test job: [f48e7a246a567e3764112e2463274c479d95cd96] https://lava.sirena.org.uk/scheduler/job/2522185
# test job: [9891b52ba12e9d5fed5901b6b5f6e0cdcd424390] https://lava.sirena.org.uk/scheduler/job/2522240
# test job: [e84141846decb77d2826e553318a608b256804e5] https://lava.sirena.org.uk/scheduler/job/2516913
# test job: [9ab637ac5d3826606947f4e861107da958eda324] https://lava.sirena.org.uk/scheduler/job/2516426
# test job: [34b4fc44e4f904fbb81335d53163ffdcb0180000] https://lava.sirena.org.uk/scheduler/job/2513607
# test job: [1696fad8b259a2d46e51cd6e17e4bcdbe02279fa] https://lava.sirena.org.uk/scheduler/job/2514118
# test job: [d3b693a13b39bce16e284e1c737874966b3a96de] https://lava.sirena.org.uk/scheduler/job/2511841
# test job: [06dba254de95b16e7793224d29daa5195de2e581] https://lava.sirena.org.uk/scheduler/job/2513766
# test job: [17c6bf433742e0c1ff5ce175145877c0194e4a7a] https://lava.sirena.org.uk/scheduler/job/2513835
# test job: [da37bfe76b5b4ccc01ed8132215098e20d78e5f3] https://lava.sirena.org.uk/scheduler/job/2511899
# test job: [501efdcb3b3ab099fc0ce2f6e668b1c4095dd476] https://lava.sirena.org.uk/scheduler/job/2500586
# test job: [2974aa42e6696a1d95b727d677dc01a71af5b998] https://lava.sirena.org.uk/scheduler/job/2502174
# test job: [d90c0f78379454d51a428e312ac6db573060185c] https://lava.sirena.org.uk/scheduler/job/2500322
# test job: [5c74a008ffc62fc57a041602b4517519c8bf9436] https://lava.sirena.org.uk/scheduler/job/2496391
# test job: [260c3fff1fefc570d8f23e87953e181d7d248861] https://lava.sirena.org.uk/scheduler/job/2494171
# test job: [7c12f6ead4672cb08b74e6f6115eb04dca8ccfa4] https://lava.sirena.org.uk/scheduler/job/2488528
# test job: [37983fad7f3ef296fa0504c8e945987459dc5487] https://lava.sirena.org.uk/scheduler/job/2489154
# test job: [ada32396f90951e12465224c04742607ca56a982] https://lava.sirena.org.uk/scheduler/job/2489236
# test job: [e02902dd493bf9c9b05353c761737ac514ad7a5c] https://lava.sirena.org.uk/scheduler/job/2489718
# test job: [507a071d9868cb60e4e76f8a06fc8eb014f59ae4] https://lava.sirena.org.uk/scheduler/job/2486375
# test job: [fed6e5084894373d76270cad4a32eb6479ad8247] https://lava.sirena.org.uk/scheduler/job/2484717
# test job: [5ebc20921b7fff9feb44de465448e17a382c9965] https://lava.sirena.org.uk/scheduler/job/2485130
# test job: [171b3663f33e1efdc97f5112f49be10b47b20fa8] https://lava.sirena.org.uk/scheduler/job/2482581
# test job: [c2bcf62ca75c541ec4297e6ff02a68ddc2e02029] https://lava.sirena.org.uk/scheduler/job/2483282
# test job: [0556bb42a84ee391a2145ddba86756f9747bc27f] https://lava.sirena.org.uk/scheduler/job/2483207
# test job: [d075cef4af6327a5de4bee7bf77591e3201e54f4] https://lava.sirena.org.uk/scheduler/job/2483468
# test job: [78dfbd4ad0be9f51de7b9a19388809254aeccd26] https://lava.sirena.org.uk/scheduler/job/2483108
# test job: [bf122191473e26a8f195308b1ba924c98424c8e1] https://lava.sirena.org.uk/scheduler/job/2482758
# test job: [fbb4c52ccdcb4a612d2b7f800aa57090eeee16d7] https://lava.sirena.org.uk/scheduler/job/2482462
# test job: [cf7c3c02fdd0dfccf4d6611714273dcb538af2cb] https://lava.sirena.org.uk/scheduler/job/2617478
# bad: [cf7c3c02fdd0dfccf4d6611714273dcb538af2cb] Add linux-next specific files for 20260330
git bisect bad cf7c3c02fdd0dfccf4d6611714273dcb538af2cb
# test job: [c99ea8b71328bb73baf24b2fb1591e076f1617a1] https://lava.sirena.org.uk/scheduler/job/2608073
# bad: [c99ea8b71328bb73baf24b2fb1591e076f1617a1] Merge branch 'clk-rpi' into clk-next
git bisect bad c99ea8b71328bb73baf24b2fb1591e076f1617a1
# test job: [672299736af6c398e867782708b7400957e62c76] https://lava.sirena.org.uk/scheduler/job/2608599
# bad: [672299736af6c398e867782708b7400957e62c76] clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks
git bisect bad 672299736af6c398e867782708b7400957e62c76
# first bad commit: [672299736af6c398e867782708b7400957e62c76] clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks
# test job: [672299736af6c398e867782708b7400957e62c76] https://lava.sirena.org.uk/scheduler/job/2608599
# bad: [672299736af6c398e867782708b7400957e62c76] clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks
git bisect bad 672299736af6c398e867782708b7400957e62c76
# first bad commit: [672299736af6c398e867782708b7400957e62c76] clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks
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