Hi Ulf,

On 01/07/25 17:17, Ulf Hansson wrote:

Changes in v3:
	- Added a couple of patches to adress problems on some Renesas
	platforms. Thanks Geert and Tomi for helping out!
	- Adressed a few comments from Saravanna and Konrad.
	- Added some tested-by tags.

Changes in v2:
	- Well, quite a lot as I discovered various problems when doing
	additional testing of corner-case. I suggest re-review from scratch,
	even if I decided to keep some reviewed-by tags.
	- Added patches to allow some drivers that needs to align or opt-out
	from the new common behaviour in genpd.

If a PM domain (genpd) is powered-on during boot, there is probably a good
reason for it. Therefore it's known to be a bad idea to allow such genpd to be
powered-off before all of its consumer devices have been probed. This series
intends to fix this problem.

We have been discussing these issues at LKML and at various Linux-conferences
in the past. I have therefore tried to include the people I can recall being
involved, but I may have forgotten some (my apologies), feel free to loop them
in.

quoted

I have tested this with QEMU with a bunch of local test-drivers and 

DT nodes.

Let me know if you want me to share this code too.

Please help review and test!

During testing on a TI platform, I observed new kernel warnings after 
applying this patch series:

ti_sci_pm_domains 44043000.system-controller:power-controller: 
sync_state() pending due to fd00000.gpu

These warnings occur when a device (in this case, the GPU) has no driver 
bound to it. The fw_devlink_dev_sync_state[0] in the core has a check 
before printing this warning. It checks whether the device driver has a 
sync_state handler OR the device bus has a sync_state handler in the 
dev_has_sync_state[1]. If both conditions are false, 
fw_devlink_dev_sync_state[0] performs an early return before printing 
the warning.

Before this patch series, both handlers were absent for device driver 
ti_sci_pm_domains and the device bus, so both conditions failed and no 
warnings were printed.

This patch series adds a sync_state handler for the bus, which now 
satisfies the second condition. So it doesn't do an early return and 
proceeds to print the warning.

[0]: https://elixir.bootlin.com/linux/v6.16/source/drivers/base/core.c#L1777
[1]: 
https://elixir.bootlin.com/linux/v6.16/source/include/linux/device.h#L909

Thanks
Sebin

Finally, a big thanks to Saravana for all the support!

Kind regards
Ulf Hansson


Saravana Kannan (1):
   driver core: Add dev_set_drv_sync_state()

Ulf Hansson (23):
   pmdomain: renesas: rcar-sysc: Add genpd OF provider at
     postcore_initcall
   pmdomain: renesas: rmobile-sysc: Move init to postcore_initcall
   pmdomain: renesas: rcar-gen4-sysc: Move init to postcore_initcall
   pmdomain: core: Prevent registering devices before the bus
   pmdomain: core: Add a bus and a driver for genpd providers
   pmdomain: core: Add the genpd->dev to the genpd provider bus
   pmdomain: core: Export a common ->sync_state() helper for genpd
     providers
   pmdomain: core: Prepare to add the common ->sync_state() support
   soc/tegra: pmc: Opt-out from genpd's common ->sync_state() support
   cpuidle: psci: Opt-out from genpd's common ->sync_state() support
   cpuidle: riscv-sbi: Opt-out from genpd's common ->sync_state() support
   pmdomain: qcom: rpmpd: Use of_genpd_sync_state()
   pmdomain: qcom: rpmhpd: Use of_genpd_sync_state()
   firmware/pmdomain: xilinx: Move ->sync_state() support to firmware
     driver
   firmware: xilinx: Don't share zynqmp_pm_init_finalize()
   firmware: xilinx: Use of_genpd_sync_state()
   driver core: Export get_dev_from_fwnode()
   pmdomain: core: Add common ->sync_state() support for genpd providers
   pmdomain: core: Default to use of_genpd_sync_state() for genpd
     providers
   pmdomain: core: Leave powered-on genpds on until late_initcall_sync
   pmdomain: core: Leave powered-on genpds on until sync_state
   cpuidle: psci: Drop redundant sync_state support
   cpuidle: riscv-sbi: Drop redundant sync_state support

  drivers/base/core.c                         |   8 +-
  drivers/cpuidle/cpuidle-psci-domain.c       |  14 --
  drivers/cpuidle/cpuidle-riscv-sbi.c         |  14 --
  drivers/firmware/xilinx/zynqmp.c            |  18 +-
  drivers/pmdomain/core.c                     | 211 ++++++++++++++++++--
  drivers/pmdomain/qcom/rpmhpd.c              |   2 +
  drivers/pmdomain/qcom/rpmpd.c               |   2 +
  drivers/pmdomain/renesas/rcar-gen4-sysc.c   |   2 +-
  drivers/pmdomain/renesas/rcar-sysc.c        |  19 +-
  drivers/pmdomain/renesas/rmobile-sysc.c     |   3 +-
  drivers/pmdomain/xilinx/zynqmp-pm-domains.c |  16 --
  drivers/soc/tegra/pmc.c                     |  26 ++-
  include/linux/device.h                      |  13 ++
  include/linux/firmware/xlnx-zynqmp.h        |   6 -
  include/linux/pm_domain.h                   |  17 ++
  15 files changed, 291 insertions(+), 80 deletions(-)