Re: [RFT PATCH v3 1/1] usb: hub: Fix flushing of delayed work used for post resume purposes

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 28.6.2025 17.46, Greg KH wrote:
> On Fri, Jun 27, 2025 at 07:43:48PM +0300, Mathias Nyman wrote:
>> Delayed work that prevents USB3 hubs from runtime-suspending too early
>> needed to be flushed in hub_quiesce() to resolve issues detected on
>> QC SC8280XP CRD board during suspend resume testing.
>>
>> This flushing did however trigger new issues on Raspberry Pi 3B+, which
>> doesn't have USB3 ports, and doesn't queue any post resume delayed work.
>>
>> The flushed 'hub->init_work' item is used for several purposes, and
>> is originally initialized with a 'NULL' work function. The work function
>> is also changed on the fly, which may contribute to the issue.
>>
>> Solve this by creating a dedicated delayed work item for post resume work,
>> and flush that delayed work in hub_quiesce()
>>
>> Cc: stable@kernel.org
>> Fixes: a49e1e2e785f ("usb: hub: Fix flushing and scheduling of delayed work that tunes runtime pm")
>> Reported-by: Mark Brown <broonie@kernel.org>
>> Closes: https://lore.kernel.org/linux-usb/aF5rNp1l0LWITnEB@finisterre.sirena.org.uk
>> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>> ---
>> v3:
>>   - Rebase on top of a49e1e2e785f ("usb: hub: Fix flushing and scheduling of delayed work that tunes runtime pm")
>>   - Rewrite commit message
>>
>> v2:
>>   - Add and use dedicated delayed work struct for post resume work
>>   - Add commit message section about dedicated work
> 
> This seems to work, want me to take this, or are you going to submit
> another one?  I'll hold off on sending the pull request to Linus for
> -rc4 because of this.
> 
> thanks,
> 
> greg k-h

Sorry about the response delay, was offline during weekend

I'll do some quick additional smoketests, suspending and disconnecting runtime suspended
chained USB3 hubs. Shouldn't take more than a couple of hours

Thanks
Mathias