On Fri, Jun 04, 2004 at 04:07:15PM -0400, Alan Stern wrote:
> Greg:
> 
> This patch includes the algorithmic changes I would like to see in 
> hub_port_debounce().  They are:
> 
>       Increase the total timeout period from 400 ms to 1500 ms.
> 
>       Check the port's connect-changed status during the polling
>       loop.
> 
>       Return as soon as the connection has been stable for the
>       required time, even if it has been stably _dis_-connected.
>       (The current code waits for the full timeout period if there
>       isn't a connection.)
> 
> In previous emails I have responded to all the concerns raised by others 
> about these changes, and I can't imagine how they could cause any trouble.
> 
>       Increasing the total timeout won't affect people with properly
>       functioning hardware.  Their connections will quickly stabilize
>       and the routine will return just as before.  People with flaky
>       hardware that takes a long time to settle down will now be able
>       to use their devices.
> 
>       Checking the connect-changed status during the polling loop will
>       make the test more conservative.  The code will be able to
>       detect transient disconnections that it would have missed
>       before, and it won't return until the connection really _is_
>       stable.  Furthermore, this makes the test compliant with the
>       USB specification, which requires the stability timer to be
>       restarted whenever a connection change occurs.
> 
>       Returning early for disconnections is a simple optimization.
>       It's more important now that the total timeout length is 1.5
>       seconds rather than 0.4 seconds.
> 
> I urge you to apply this patch and for people to try it out.  If there do 
> turn out to be problems... the patch is very small, well-contained, and 
> easy to revert.

Nice, thanks for separating this all out like this.

Applied, thanks.

greg k-h


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