Re: [PATCH] usbmouse: random freeze/hangup; synchronize irq completion

[Jordi Pujol <jordipujolp@gmail.com>]

A Dilluns 14 Febrer 2011 16:00:24, Alan Stern va escriure:
> 	It calls mutex_lock(), which can sleep, from within an URB
> 	completion routine, which runs with interrupts disabled.
> 
> 	It doesn't synchronize the completion _with_ anything else,
> 	i.e., it calls mutex_lock() in only one place.
this routine is synchronized with himself.
I said synchronize thinking about synchronized routines that are pieces of 
code scheduled to be executed only in a single thread simultaneously; 
therefore a new call to this routine can not be executed until a previous call 
has been completed.

> 
> Whatever is causing your problem, this is not the proper solution.
Yes, that this is not a patch to be included in the kernel, it's only a 
testing patch, but it solves the hangup. and so this probes that there is some 
kind of problem related to the urb update process; I think the problem should 
be external to this routine.

searching the web, some people has found problems like this, example:
- [ubuntu] Ubuntu 10.04 (Lucid Lynx) Random Freeze / Hang-up

Consider this as an idea to point out the problem and, if possible, someone 
more expert help to look for a good solution.

Jordi Pujol

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