From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754815AbaC3Xzu (ORCPT ); Sun, 30 Mar 2014 19:55:50 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37332 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754605AbaC3Xn2 (ORCPT ); Sun, 30 Mar 2014 19:43:28 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Alan Stern" , "Greg Kroah-Hartman" , "Peter Chen" Date: Mon, 31 Mar 2014 00:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 126/200] USB: EHCI: add delay during suspend to prevent erroneous wakeups In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.56-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 3e8d6d85adedc59115a564c0a54b36e42087c4d9 upstream. High-speed USB connections revert back to full-speed signalling when the device goes into suspend. This takes several milliseconds, and during that time it's not possible to tell reliably whether the device has been disconnected. On some platforms, the Wake-On-Disconnect circuitry gets confused during this intermediate state. It generates a false wakeup signal, which can prevent the controller from going to sleep. To avoid this problem, this patch adds a 5-ms delay to the ehci_bus_suspend() routine if any ports have to switch over to full-speed signalling. (Actually, the delay was already present for devices using a particular kind of PHY power management; the patch merely causes the delay to be used more widely.) Signed-off-by: Alan Stern Reviewed-by: Peter Chen Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: - Adjust context - s/has_tdi_phy_lpm/has_hostpc/ - Always re-lock ehci->lock after the sleep] Signed-off-by: Ben Hutchings --- --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -207,6 +207,7 @@ static int ehci_bus_suspend (struct usb_ int port; int mask; int changed; + bool fs_idle_delay; ehci_dbg(ehci, "suspend root hub\n"); @@ -249,6 +250,7 @@ static int ehci_bus_suspend (struct usb_ ehci->bus_suspended = 0; ehci->owned_ports = 0; changed = 0; + fs_idle_delay = false; port = HCS_N_PORTS(ehci->hcs_params); while (port--) { u32 __iomem *reg = &ehci->regs->port_status [port]; @@ -279,16 +281,34 @@ static int ehci_bus_suspend (struct usb_ if (t1 != t2) { ehci_vdbg (ehci, "port %d, %08x -> %08x\n", port + 1, t1, t2); + /* + * On some controllers, Wake-On-Disconnect will + * generate false wakeup signals until the bus + * switches over to full-speed idle. For their + * sake, add a delay if we need one. + */ + if ((t2 & PORT_WKDISC_E) && + ehci_port_speed(ehci, t2) == + USB_PORT_STAT_HIGH_SPEED) + fs_idle_delay = true; ehci_writel(ehci, t2, reg); changed = 1; } } + spin_unlock_irq(&ehci->lock); + + if ((changed && ehci->has_hostpc) || fs_idle_delay) { + /* + * Wait for HCD to enter low-power mode or for the bus + * to switch to full-speed idle. + */ + usleep_range(5000, 5500); + } + + spin_lock_irq(&ehci->lock); if (changed && ehci->has_hostpc) { - spin_unlock_irq(&ehci->lock); - msleep(5); /* 5 ms for HCD to enter low-power mode */ spin_lock_irq(&ehci->lock); - port = HCS_N_PORTS(ehci->hcs_params); while (port--) { u32 __iomem *hostpc_reg;