This is a note to let you know that I've just added the patch titled
usb: ehci: change order of register cleanup during shutdown
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-ehci-change-order-of-register-cleanup-during-shutdown.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bc337b51508beb2d039aff5074a76cfe1c212030 Mon Sep 17 00:00:00 2001
From: Marc Ohlf <ohlf@xxxxxxxxxx>
Date: Wed, 3 Aug 2016 11:51:54 +0200
Subject: usb: ehci: change order of register cleanup during shutdown
From: Marc Ohlf <ohlf@xxxxxxxxxx>
commit bc337b51508beb2d039aff5074a76cfe1c212030 upstream.
In ehci_turn_off_all_ports() all EHCI port registers are cleared to zero.
On some hardware, this can lead to an system hang,
when ehci_port_power() accesses the already cleared registers.
This patch changes the order of cleanup.
First call ehci_port_power() which respects the current bits in
port status registers
and afterwards cleanup the hard way by setting everything to zero.
Signed-off-by: Marc Ohlf <ohlf@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ehci-hcd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -332,11 +332,11 @@ static void ehci_turn_off_all_ports(stru
int port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
- ehci_writel(ehci, PORT_RWC_BITS,
- &ehci->regs->port_status[port]);
spin_unlock_irq(&ehci->lock);
ehci_port_power(ehci, port, false);
spin_lock_irq(&ehci->lock);
+ ehci_writel(ehci, PORT_RWC_BITS,
+ &ehci->regs->port_status[port]);
}
}
Patches currently in stable-queue which might be from ohlf@xxxxxxxxxx are
queue-4.4/usb-ehci-change-order-of-register-cleanup-during-shutdown.patch
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