Re: [PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during system suspend/resume

[Roger Quadros]

On 23/01/18 14:41, Roger Quadros wrote:
> Hi Manu,
> 
> On 23/01/18 05:45, Manu Gautam wrote:
>> Hi,
>>
>>
>> On 1/22/2018 6:31 PM, Roger Quadros wrote:
>>> Adding/removing host/gadget controller before .pm_complete()
>>> causes a lock-up. Let's prevent any dual-role state change
>>> between .pm_prepare() and .pm_complete() to fix this.
>>
>> What kind of lock-up are you seeing? Some hardware lockup or software deadlock?
>> IMO using a freezable_wq for drd_work should address that?
>>
> 
> I was seeing a software deadlock. freezable_wq is a good idea. I'll try it out.

using freezable_wq doesn't get rid of the deadlock.
If I use freezable_wq plus add some delay before I do a dwc3_host_init()
in the work function then it starts to work.

As dependence on delay looks fragile so I'll stick to the current implementation
based on .pm_prepare/complete().

-- 
cheers,
-roger

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