USB: OHCI: fix problem with global suspend on ATI controllers
authorAlan Stern <stern@rowland.harvard.edu>
Thu, 1 May 2014 19:21:42 +0000 (15:21 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 7 Jun 2014 20:25:32 +0000 (13:25 -0700)
commitdee037703a4144fcf190b17aaa7543c907f7c375
tree2f13c5ec60704a0e2dcac0cd6b9c788b8f1abe9d
parente044bf34f58acd63b408794326795b6e6b87f90a
USB: OHCI: fix problem with global suspend on ATI controllers

commit c1db30a2a79eb59997b13b8cabf2a50bea9f04e1 upstream.

Some OHCI controllers from ATI/AMD seem to have difficulty with
"global" USB suspend, that is, suspending an entire USB bus without
setting the suspend feature for each port connected to a device.  When
we try to resume the child devices, the controller gives timeout
errors on the unsuspended ports, requiring resets, and can even cause
ohci-hcd to hang; see

http://marc.info/?l=linux-usb&m=139514332820398&w=2

and the following messages.

This patch fixes the problem by adding a new quirk flag to ohci-hcd.
The flag causes the ohci_rh_suspend() routine to suspend each
unsuspended, enabled port before suspending the root hub.  This
effectively converts the "global" suspend to an ordinary root-hub
suspend.  There is no need to unsuspend these ports when the root hub
is resumed, because the child devices will be resumed anyway in the
course of a normal system resume ("global" suspend is never used for
runtime PM).

This patch should be applied to all stable kernels which include
commit 0aa2832dd0d9 (USB: use "global suspend" for system sleep on
USB-2 buses) or a backported version thereof.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Peter Münster <pmlists@free.fr>
Tested-by: Peter Münster <pmlists@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/host/ohci-hub.c
drivers/usb/host/ohci-pci.c
drivers/usb/host/ohci.h