Re: [PATCH v1] PM: sleep: Do not flag runtime PM workqueue as freezable

[YangYang <yang.yang@vivo.com>]

On 2025/12/2 3:58, Rafael J. Wysocki wrote:
> On Monday, December 1, 2025 7:47:46 PM CET Rafael J. Wysocki wrote:
>> On Mon, Dec 1, 2025 at 10:46 AM YangYang <yang.yang@vivo.com> wrote:
> 
> [cut]
> 
>> If blk_queue_enter() or __bio_queue_enter() is allowed to race with
>> disabling runtime PM for q->dev, failure to resume q->dev is alway
>> possible and there are no changes that can be made to
>> pm_runtime_disable() to prevent that from happening.  If
>> __pm_runtime_disable() wins the race, it will increment
>> power.disable_depth and rpm_resume() will bail out when it sees that
>> no matter what.
>>
>> You should not conflate "runtime PM doesn't work when it is disabled"
>> with "asynchronous runtime PM doesn't work after freezing the PM
>> workqueue".  They are both true, but they are not the same.
> 
> So I've been testing the patch below for a few days and it will eliminate
> the latter, but even after this patch runtime PM will be disabled in
> device_suspend_late() and if the problem you are facing is still there
> after this patch, it will need to dealt with at the driver level.
> 
> Generally speaking, driver involvement is needed to make runtime PM and
> system suspend/resume work together in the majority of cases.
> 

Thank you. I'll perform some tests with this patch applied.