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* [PATCH v2 0/9] driver core / pmdomain: Add support for fined grained sync_state
@ 2026-04-10 10:40 Ulf Hansson
  2026-04-10 10:40 ` [PATCH v2 1/9] driver core: Enable suppliers to implement fine grained sync_state support Ulf Hansson
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: Ulf Hansson @ 2026-04-10 10:40 UTC (permalink / raw)
  To: Saravana Kannan, Rafael J . Wysocki, Greg Kroah-Hartman, linux-pm
  Cc: Sudeep Holla, Cristian Marussi, Kevin Hilman, Stephen Boyd,
	Marek Szyprowski, Bjorn Andersson, Abel Vesa, Peng Fan,
	Tomi Valkeinen, Maulik Shah, Konrad Dybcio, Thierry Reding,
	Jonathan Hunter, Geert Uytterhoeven, Dmitry Baryshkov,
	Ulf Hansson, linux-arm-kernel, linux-kernel

Since the introduction [1] of the common sync_state support for pmdomains
(genpd), we have encountered a lot of various interesting problems. In most
cases the new behaviour of genpd triggered some weird platform specific bugs.

That said, in LPC in Tokyo me and Saravana hosted a session to walk through the
remaining limitations that we have found for genpd's sync state support. In
particular, we discussed the problems we have for the so-called onecell power
domain providers, where a single provider typically provides multiple
independent power domains, all with their own set of consumers.

Note that, onecell power domain providers are very common. It's being used by
many SoCs/platforms/technologies. To name a few:
SCMI, Qualcomm, NXP, Mediatek, Renesas, TI, etc.

Anyway, in these cases, the generic sync_state mechanism with fw_devlink isn't
fine grained enough, as we end up waiting for all consumers for all power
domains before the ->sync_callback gets called for the supplier/provider. In
other words, we may end up keeping unused power domains powered-on, for no good
reasons.

The series intends to fix this problem. Please have a look at the commit
messages for more details and help review/test!

Kind regards
Ulf Hansson

[1]
https://lore.kernel.org/all/20250701114733.636510-1-ulf.hansson@linaro.org/

Ulf Hansson (9):
  driver core: Enable suppliers to implement fine grained sync_state
    support
  driver core: Add dev_set_drv_queue_sync_state()
  pmdomain: core: Move genpd_get_from_provider()
  pmdomain: core: Add initial fine grained sync_state support
  pmdomain: core: Extend fine grained sync_state to more onecell
    providers
  pmdomain: core: Export a common function for ->queue_sync_state()
  pmdomain: renesas: rcar-gen4-sysc: Drop GENPD_FLAG_NO_STAY_ON
  pmdomain: renesas: rcar-sysc: Drop GENPD_FLAG_NO_STAY_ON
  pmdomain: renesas: rmobile-sysc: Drop GENPD_FLAG_NO_STAY_ON

 drivers/base/core.c                       |   7 +-
 drivers/pmdomain/core.c                   | 205 ++++++++++++++++++----
 drivers/pmdomain/renesas/rcar-gen4-sysc.c |   1 -
 drivers/pmdomain/renesas/rcar-sysc.c      |   1 -
 drivers/pmdomain/renesas/rmobile-sysc.c   |   3 +-
 include/linux/device.h                    |  12 ++
 include/linux/device/driver.h             |   7 +
 include/linux/pm_domain.h                 |   3 +
 8 files changed, 197 insertions(+), 42 deletions(-)

-- 
2.43.0



^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2026-04-10 10:41 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-10 10:40 [PATCH v2 0/9] driver core / pmdomain: Add support for fined grained sync_state Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 1/9] driver core: Enable suppliers to implement fine grained sync_state support Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 2/9] driver core: Add dev_set_drv_queue_sync_state() Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 3/9] pmdomain: core: Move genpd_get_from_provider() Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 4/9] pmdomain: core: Add initial fine grained sync_state support Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 5/9] pmdomain: core: Extend fine grained sync_state to more onecell providers Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 6/9] pmdomain: core: Export a common function for ->queue_sync_state() Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 7/9] pmdomain: renesas: rcar-gen4-sysc: Drop GENPD_FLAG_NO_STAY_ON Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 8/9] pmdomain: renesas: rcar-sysc: " Ulf Hansson
2026-04-10 10:40 ` [PATCH v2 9/9] pmdomain: renesas: rmobile-sysc: " Ulf Hansson

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