From patchwork Mon Jul 9 15:09:21 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alan Stern X-Patchwork-Id: 169876 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id D52A62C01D3 for ; Tue, 10 Jul 2012 01:09:25 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755007Ab2GIPJX (ORCPT ); Mon, 9 Jul 2012 11:09:23 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:38408 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754145Ab2GIPJW (ORCPT ); Mon, 9 Jul 2012 11:09:22 -0400 Received: (qmail 6159 invoked by uid 2102); 9 Jul 2012 11:09:21 -0400 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 9 Jul 2012 11:09:21 -0400 Date: Mon, 9 Jul 2012 11:09:21 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Bjorn Helgaas cc: AceLan Kao , "Rafael J. Wysocki" , =?UTF-8?Q?D=C3=A2niel_Fraga?= , Javier Marcet , Andrey Rahmatullin , Oleksij Rempel , Pavel Pisa , , USB list Subject: [PATCH] PCI: EHCI: fix crash during suspend on ASUS computers Message-ID: MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Quite a few ASUS computers experience a nasty problem, related to the EHCI controllers, when going into system suspend. It was observed that the problem didn't occur if the controllers were not put into the D3 power state before starting the suspend, and commit 151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during suspend on ASUS computers) was created to do this. It turned out this approach messed up other computers that didn't have the problem -- it prevented USB wakeup from working. Consequently commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b (USB: add NO_D3_DURING_SLEEP flag and revert 151b61284776be2) was merged; it reverted the earlier commit and added a whitelist of known good board names. Now we know the actual cause of the problem. Thanks to AceLan Kao for tracking it down. According to him, an engineer at ASUS explained that some of their BIOSes contain a bug that was added in an attempt to work around a problem in early versions of Windows. When the computer goes into S3 suspend, the BIOS tries to verify that the EHCI controllers were first quiesced by the OS. Nothing's wrong with this, but the BIOS does it by checking that the PCI COMMAND registers contain 0 without checking the controllers' power state. If the register isn't 0, the BIOS assumes the controller needs to be quiesced and tries to do so. This involves making various MMIO accesses to the controller, which don't work very well if the controller is already in D3. The end result is a system hang or memory corruption. Since the value in the PCI COMMAND register doesn't matter once the controller has been suspended, and since the value will be restored anyway when the controller is resumed, we can work around the BIOS bug simply by setting the register to 0 during system suspend. This patch (as1590) does so and also reverts the second commit mentioned above, which is now unnecessary. In theory we could do this for every PCI device. However to avoid introducing new problems, the patch restricts itself to EHCI host controllers. Finally the affected systems can suspend with USB wakeup working properly. Signed-off-by: Alan Stern Tested-by: Dâniel Fraga Tested-by: Javier Marcet Tested-by: Andrey Rahmatullin Tested-by: Oleksij Rempel Tested-by: Pavel Pisa CC: Acked-by: Greg Kroah-Hartman Acked-by: Rafael J. Wysocki Acked-by: Bjorn Helgaas --- drivers/pci/pci-driver.c | 12 ++++++++++++ drivers/pci/pci.c | 5 ----- drivers/pci/quirks.c | 26 -------------------------- include/linux/pci.h | 2 -- 4 files changed, 12 insertions(+), 33 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: usb-3.4/drivers/pci/pci.c ================================================================== --- usb-3.4.orig/drivers/pci/pci.c +++ usb-3.4/drivers/pci/pci.c @@ -1744,11 +1744,6 @@ int pci_prepare_to_sleep(struct pci_dev if (target_state == PCI_POWER_ERROR) return -EIO; - /* Some devices mustn't be in D3 during system sleep */ - if (target_state == PCI_D3hot && - (dev->dev_flags & PCI_DEV_FLAGS_NO_D3_DURING_SLEEP)) - return 0; - pci_enable_wake(dev, target_state, device_may_wakeup(&dev->dev)); error = pci_set_power_state(dev, target_state); Index: usb-3.4/drivers/pci/quirks.c =================================================================== --- usb-3.4.orig/drivers/pci/quirks.c +++ usb-3.4/drivers/pci/quirks.c @@ -2929,32 +2929,6 @@ static void __devinit disable_igfx_irq(s DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0102, disable_igfx_irq); DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x010a, disable_igfx_irq); -/* - * The Intel 6 Series/C200 Series chipset's EHCI controllers on many - * ASUS motherboards will cause memory corruption or a system crash - * if they are in D3 while the system is put into S3 sleep. - */ -static void __devinit asus_ehci_no_d3(struct pci_dev *dev) -{ - const char *sys_info; - static const char good_Asus_board[] = "P8Z68-V"; - - if (dev->dev_flags & PCI_DEV_FLAGS_NO_D3_DURING_SLEEP) - return; - if (dev->subsystem_vendor != PCI_VENDOR_ID_ASUSTEK) - return; - sys_info = dmi_get_system_info(DMI_BOARD_NAME); - if (sys_info && memcmp(sys_info, good_Asus_board, - sizeof(good_Asus_board) - 1) == 0) - return; - - dev_info(&dev->dev, "broken D3 during system sleep on ASUS\n"); - dev->dev_flags |= PCI_DEV_FLAGS_NO_D3_DURING_SLEEP; - device_set_wakeup_capable(&dev->dev, false); -} -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1c26, asus_ehci_no_d3); -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1c2d, asus_ehci_no_d3); - static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f, struct pci_fixup *end) { Index: usb-3.4/include/linux/pci.h =================================================================== --- usb-3.4.orig/include/linux/pci.h +++ usb-3.4/include/linux/pci.h @@ -176,8 +176,6 @@ enum pci_dev_flags { PCI_DEV_FLAGS_NO_D3 = (__force pci_dev_flags_t) 2, /* Provide indication device is assigned by a Virtual Machine Manager */ PCI_DEV_FLAGS_ASSIGNED = (__force pci_dev_flags_t) 4, - /* Device causes system crash if in D3 during S3 sleep */ - PCI_DEV_FLAGS_NO_D3_DURING_SLEEP = (__force pci_dev_flags_t) 8, }; enum pci_irq_reroute_variant { Index: usb-3.4/drivers/pci/pci-driver.c =================================================================== --- usb-3.4.orig/drivers/pci/pci-driver.c +++ usb-3.4/drivers/pci/pci-driver.c @@ -748,6 +748,18 @@ static int pci_pm_suspend_noirq(struct d pci_pm_set_unknown_state(pci_dev); + /* + * Some BIOSes from ASUS have a bug: If a USB EHCI host controller's + * PCI COMMAND register isn't 0, the BIOS assumes that the controller + * hasn't been quiesced and tries to turn it off. If the controller + * is already in D3, this can hang or cause memory corruption. + * + * Since the value of the COMMAND register doesn't matter once the + * device has been suspended, we can safely set it to 0 here. + */ + if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI) + pci_write_config_word(pci_dev, PCI_COMMAND, 0); + return 0; }