On 1/23/26 2:50 PM, Geert Uytterhoeven wrote:
Hello everyone,
On Fri, 23 Jan 2026 at 14:36, Matt Coster <[email protected]> wrote:
On 22/01/2026 16:08, Geert Uytterhoeven wrote:
Call the dev_pm_domain_attach_list() and dev_pm_domain_detach_list()
helpers instead of open-coding multi PM Domain handling.
This changes behavior slightly:
- The new handling is also applied in case of a single PM Domain,
- PM Domains are now referred to by index instead of by name, but
"make dtbs_check" enforces the actual naming and ordering anyway,
- There are no longer device links created between virtual domain
devices, only between virtual devices and the parent device.
We still need this guarantee, both at start and end of day. In the
current implementation dev_pm_domain_attach_list() iterates forwards,
but so does dev_pm_domain_detach_list(). Even if we changed that, I'd
prefer not to rely on the implementation details when we can declare the
dependencies explicitly.
Note that on R-Car, the PM Domains are nested (see e.g. r8a7795_areas[]),
so they are always (un)powered in the correct order. But that may not
be the case in the integration on other SoCs.
We had/have a patch (attached) kicking around internally to use the
*_list() functions but keep the inter-domain links in place; it got held
up by discussions as to whether we actually need those dependencies for
the hardware to behave correctly. Your patch spurred me to run around
the office and nag people a bit, and it seems we really do need to care
about the ordering.
OK.
Can you add the links back in for a V2 or I can properly send the
attached patch instead, I don't mind either way.
Please move forward with your patch, you are the expert.
I prefer not to be blamed for any breakage ;-)
Has there been any progress on fixing this kernel crash ?
There are already two proposed solutions, but no fix is upstream.
--
Best regards,
Marek Vasut
