Re: [PATCH] drm/imagination: Convert to dev_pm_domain_{at,de}tach_list()

[Marek Vasut <marek.vasut@mailbox.org>]

On 2/12/26 10:00 AM, Matt Coster wrote:
> On 11/02/2026 19:17, Marek Vasut wrote:
>> On 1/23/26 2:50 PM, Geert Uytterhoeven wrote:
>>
>> Hello everyone,
>>
>>> On Fri, 23 Jan 2026 at 14:36, Matt Coster <Matt.Coster@imgtec.com> 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.
>>
> 
> Yes and no. Our patch to use dev_pm_domain_attach_list() has landed in
> drm-misc-next as commit e19cc5ab347e3 ("drm/imagination: Use
> dev_pm_domain_attach_list()"), but this does not fix the underlying
> issue of missing synchronization in the PM core[1] is still unresolved
> as far as I'm aware.

OK, but the pvr driver can currently easily crash the kernel on boot if 
firmware is missing, so that should be fixed soon, right ?

I added the regressions list onto CC, because this seems like a problem 
worth tracking.