Re: [PATCH] USB: improve port transitions when EHCI starts up

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On Wed, Mar 27, 2013 at 04:13:36PM -0400, Alan Stern wrote:
> It seems to be getting more common recently for EHCI host controllers
> to be probed after their companion UHCI or OHCI controllers.  This may
> be caused partly by splitting the ehci-pci driver out from ehci-hcd,
> or it may be caused by changes in the way the kernel does driver
> probing.
> 
> Regardless, it has a tendency to cause problems.  When an EHCI
> controller is initialized, it takes ownership of all the ports away
> from the companions.  In effect, it forcefully disconnects all the USB
> devices that may already be using a companion controller.
> 
> This patch (as1672) tries to make the transition more orderly by
> deconfiguring the root hubs for all the companion controllers before
> initializing the EHCI controller, and reconfiguring them afterward.
> The result is a soft disconnect rather than a hard one.
> 
> Internally, the patch refactors the code involved in associating EHCI
> controllers with their companions.  The old approach, in which a
> single function is called with an argument telling it what to do (the
> companion_action enum), has been replaced with a scheme using multiple
> callback functions, each performing a single task.
> 
> This patch won't solve all the problems people encounter when their
> EHCI controllers start up, but it will at least reduce the number of
> error messages generated by the unexpected disconnections.
> 
> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Tested-by: Jenya Y <jy.gerstmaier@xxxxxxxxx>
> 
> ---
> 
>  drivers/usb/core/hcd-pci.c |  216 ++++++++++++++++++++++++++-------------------
>  1 file changed, 129 insertions(+), 87 deletions(-)

This patch doesn't apply to my tree:

checking file drivers/usb/core/hcd-pci.c
Hunk #2 succeeded at 221 (offset 5 lines).
Hunk #3 FAILED at 243.
Hunk #4 succeeded at 270 (offset 5 lines).
Hunk #5 succeeded at 313 (offset 5 lines).
Hunk #6 succeeded at 481 (offset 5 lines).
1 out of 6 hunks FAILED

What branch did you make it against?  Just to be sure, I merged both
branches together, and that still didn't work.

confused,

greg k-h
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