Re: Sleeping inside spinlock in force feedback input event code

Jiri Kosina wrote:
> On Sat, 4 Oct 2008, Anssi Hannula wrote:
>
>   
>>> There were some changes in the code due to hidbus getting finally 
>>> merged, but it should be rather trivial to solve.
>>>       
>> AFAICS no changes are needed, it applies to hid.git#mm fine.
>>     
>
> You are right.
>
> Could you please send me the patch with the changelog? I will then merge 
> it for 2.6.28.
>
> Thanks,
>
>   

From: Anssi Hannula <anssi.hannula <at> gmail.com>
Subject: HID: fix a lockup regression when using force feedback on a PID device

Commit 8006479c9b75fb6594a7b746af3d7f1fbb68f18f introduced a spinlock in
input_dev->event_lock, which is locked when handling input events.
However, the hid-pidff driver sleeps when handling events as it waits for
reports being sent to the device before changing the report contents
again.
This causes a system lockup when trying to use force feedback with a PID
device, a regression introduced in 2.6.24 and 2.6.23.15.