Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935145AbaDJD7M (ORCPT ); Wed, 9 Apr 2014 23:59:12 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:41168 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934905AbaDJDWf (ORCPT ); Wed, 9 Apr 2014 23:22:35 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sarah Sharp , Ben Hutchings , Yang Yingliang Subject: [PATCH 3.4 094/134] xhci: Dont enable/disable RWE on bus suspend/resume. Date: Wed, 9 Apr 2014 20:23:30 -0700 Message-Id: <20140410032311.812824539@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140410032259.587501440@linuxfoundation.org> References: <20140410032259.587501440@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sarah Sharp commit f217c980ca980e3a645b7485ea5eae9a747f4945 upstream. The RWE bit of the USB 2.0 PORTPMSC register is supposed to enable remote wakeup for devices in the lower power link state L1. It has nothing to do with the device suspend remote wakeup from L2. The RWE bit is designed to be set once (when USB 2.0 LPM is enabled for the port) and cleared only when USB 2.0 LPM is disabled for the port. The xHCI bus suspend method was setting the RWE bit erroneously, and the bus resume method was clearing it. The xHCI 1.0 specification with errata up to Aug 12, 2012 says in section 4.23.5.1.1.1 "Hardware Controlled LPM": "While Hardware USB2 LPM is enabled, software shall not modify the HIRDBESL or RWE fields of the USB2 PORTPMSC register..." If we have previously enabled USB 2.0 LPM for a device, that means when the USB 2.0 bus is resumed, we violate the xHCI specification by clearing RWE. It also means that after a bus resume, the host would think remote wakeup is disabled from L1 for ports with USB 2.0 Link PM enabled, which is not what we want. This patch should be backported to kernels as old as 3.2, that contain the commit 65580b4321eb36f16ae8b5987bfa1bb948fc5112 "xHCI: set USB2 hardware LPM". That was the first kernel that supported USB 2.0 Link PM. Signed-off-by: Sarah Sharp [bwh: Backported to 3.2: deleted code was cosmetically different] Signed-off-by: Ben Hutchings Cc: Yang Yingliang Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-hub.c | 28 ---------------------------- 1 file changed, 28 deletions(-) --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1048,20 +1048,6 @@ int xhci_bus_suspend(struct usb_hcd *hcd t1 = xhci_port_state_to_neutral(t1); if (t1 != t2) xhci_writel(xhci, t2, port_array[port_index]); - - if (hcd->speed != HCD_USB3) { - /* enable remote wake up for USB 2.0 */ - __le32 __iomem *addr; - u32 tmp; - - /* Add one to the port status register address to get - * the port power control register address. - */ - addr = port_array[port_index] + 1; - tmp = xhci_readl(xhci, addr); - tmp |= PORT_RWE; - xhci_writel(xhci, tmp, addr); - } } hcd->state = HC_STATE_SUSPENDED; bus_state->next_statechange = jiffies + msecs_to_jiffies(10); @@ -1140,20 +1126,6 @@ int xhci_bus_resume(struct usb_hcd *hcd) xhci_ring_device(xhci, slot_id); } else xhci_writel(xhci, temp, port_array[port_index]); - - if (hcd->speed != HCD_USB3) { - /* disable remote wake up for USB 2.0 */ - __le32 __iomem *addr; - u32 tmp; - - /* Add one to the port status register address to get - * the port power control register address. - */ - addr = port_array[port_index] + 1; - tmp = xhci_readl(xhci, addr); - tmp &= ~PORT_RWE; - xhci_writel(xhci, tmp, addr); - } } (void) xhci_readl(xhci, &xhci->op_regs->command); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/