linux-kernel - [33/78] ehci: Check individual port status registers on resume

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Date:	Mon, 21 Mar 2011 16:01:49 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Matthew Garrett <mjg@...hat.com>
Subject: [33/78] ehci: Check individual port status registers on resume

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Matthew Garrett <mjg@...hat.com>

commit 294d95f2cbc2aef5346258f216cd9df570e271a5 upstream.

If a device plug/unplug is detected on an ATI SB700 USB controller in D3,
it appears to set the port status register but not the controller status
register. As a result we'll fail to detect the plug event. Check the port
status register on resume as well in order to catch this case.

Signed-off-by: Matthew Garrett <mjg@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/usb/host/ehci-hub.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -106,6 +106,27 @@ static void ehci_handover_companion_port
 	ehci->owned_ports = 0;
 }
 
+static int ehci_port_change(struct ehci_hcd *ehci)
+{
+	int i = HCS_N_PORTS(ehci->hcs_params);
+
+	/* First check if the controller indicates a change event */
+
+	if (ehci_readl(ehci, &ehci->regs->status) & STS_PCD)
+		return 1;
+
+	/*
+	 * Not all controllers appear to update this while going from D3 to D0,
+	 * so check the individual port status registers as well
+	 */
+
+	while (i--)
+		if (ehci_readl(ehci, &ehci->regs->port_status[i]) & PORT_CSC)
+			return 1;
+
+	return 0;
+}
+
 static void ehci_adjust_port_wakeup_flags(struct ehci_hcd *ehci,
 		bool suspending, bool do_wakeup)
 {
@@ -173,7 +194,7 @@ static void ehci_adjust_port_wakeup_flag
 	}
 
 	/* Does the root hub have a port wakeup pending? */
-	if (!suspending && (ehci_readl(ehci, &ehci->regs->status) & STS_PCD))
+	if (!suspending && ehci_port_change(ehci))
 		usb_hcd_resume_root_hub(ehci_to_hcd(ehci));
 
 	spin_unlock_irqrestore(&ehci->lock, flags);


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