On Wed, Nov 07, 2012 at 06:36:46PM +0530, Bhavik Kothari wrote:
> Hi Greg,
> 
> Our host controller sets PRC and CSC bits at the time of initialization
> even though no USB device is attached. At the time of initialization,
> hub_probe() gets called and in-turn it calls hub_activate().
> hub_activate() clears the CSC bit, but PRC bit does not get cleared (in
> linux 3.6.1). hub_events() has functionality to clear the PRC bit, but
> initially there is no events from HUB, so hub_events() may not clear the
> PRC bit. Due to this behavior, when we try to insert a USB device,
> interrupt does not generate (because, earlier, PRC bit was set and not
> cleared) and USB device does not get enumerated.
> 
> Below Patch allows to clear PRC bit in hub_activate() function. So,
> above issue gets resolved.
> 
> This patch is currently against a linux 3.6.1 kernel, for the x86
> architecture.

The USB code works on all architectures :)

> Let me know in case of any concern.

So why do this on all host controllers?  Why not just clear the bit for
your devices based on a device id or some other identifier?  What
happens if you clear this on a different manufacturer's device?

Also, I would like to get an ack from Alan on this before I accept it.

thanks,

greg k-h
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