EHCI: only power off port if over-current is active
authorSergei Shtylyov <sshtylyov@ru.mvista.com>
Wed, 6 Jul 2011 19:19:38 +0000 (23:19 +0400)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 5 Aug 2011 04:58:40 +0000 (21:58 -0700)
commite151a2a6651a0a46fc03a845614b23c3b630042e
tree7441c11d68c30947ff850a24aefad57842865843
parent569f3720370818fe5c9d69a11217602b89ae3908
EHCI: only power off port if over-current is active

commit 81463c1d707186adbbe534016cd1249edeab0dac upstream.

MAX4967 USB power supply chip we use on our boards signals over-current when
power is not enabled; once it's enabled, over-current signal returns to normal.
That unfortunately caused the endless stream of "over-current change on port"
messages. The EHCI root hub code reacts on every over-current signal change
with powering off the port -- such change event is generated the moment the
port power is enabled, so once enabled the power is immediately cut off.
I think we should only cut off power when we're seeing the active over-current
signal, so I'm adding such check to that code. I also think that the fact that
we've cut off the port power should be reflected in the result of GetPortStatus
request immediately, hence I'm adding a PORTSCn register readback after write...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/host/ehci-hub.c