Re: [PATCH] Wait for child devices to go away before deleting a connection

[Brian Rogers <brian@xyzw.org>]

Marcel Holtmann wrote:
> Hi Brian,
>
>   
>> This patch fixes the device removal order when a connection is closed, 
>> which allows HAL to see the remove event and prevents a bunch of 
>> duplicate devices from piling up and eventually hitting the limit for 
>> the for input devices in X.
>>
>> Posting for discussion since I used a polling loop (with a sleep) to 
>> wait for child devices to go away. I assume it'd be preferable to wait 
>> in a more proper way. In that case, before I start, is this the right 
>> place to be waiting?
>>     
>
> since this is executed in a workqueue, you could easily sleep here
> without any problems. However why do you need to sleep at all. The
> device_move should sleep until the device is moved away, doesn't it?
>   

The moves do complete before the connection is removed, but it seems bad 
to me to just move the child devices away rather than letting them close 
down and be removed directly from the original location where they were 
created. HAL thinks so, too: it still doesn't catch the input device 
removal if they are moved away before they are deleted.

> Kay, David, wouldn't be pinning of the parent device here be enough to
> get this done in a clean way?
>   

If there's a way that the connection can be pinned until the child 
devices go away, that definitely sounds cleaner to me.