From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57318 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028AbdC1MNw (ORCPT ); Tue, 28 Mar 2017 08:13:52 -0400 Subject: Patch "PCI: Add comments about ROM BAR updating" has been added to the 4.4-stable tree To: sumit.semwal@linaro.org, alexander.levin@verizon.com, bhelgaas@google.com, gregkh@linuxfoundation.org, gwshan@linux.vnet.ibm.com Cc: , From: Date: Tue, 28 Mar 2017 14:13:10 +0200 In-Reply-To: <1490458699-24484-8-git-send-email-sumit.semwal@linaro.org> Message-ID: <149070319021196@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled PCI: Add comments about ROM BAR updating 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: pci-add-comments-about-rom-bar-updating.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 know about it. >>From foo@baz Tue Mar 28 13:59:27 CEST 2017 From: Sumit Semwal Date: Sat, 25 Mar 2017 21:48:07 +0530 Subject: PCI: Add comments about ROM BAR updating To: stable@vger.kernel.org Cc: Bjorn Helgaas , Sasha Levin , Greg Kroah-Hartman , Sumit Semwal Message-ID: <1490458699-24484-8-git-send-email-sumit.semwal@linaro.org> From: Sumit Semwal From: Bjorn Helgaas [ Upstream commit 0b457dde3cf8b7c76a60f8e960f21bbd4abdc416 ] pci_update_resource() updates a hardware BAR so its address matches the kernel's struct resource UNLESS it's a disabled ROM BAR. We only update those when we enable the ROM. It's not obvious from the code why ROM BARs should be handled specially. Apparently there are Matrox devices with defective ROM BARs that read as zero when disabled. That means that if pci_enable_rom() reads the disabled BAR, sets PCI_ROM_ADDRESS_ENABLE (without re-inserting the address), and writes it back, it would enable the ROM at address zero. Add comments and references to explain why we can't make the code look more rational. The code changes are from 755528c860b0 ("Ignore disabled ROM resources at setup") and 8085ce084c0f ("[PATCH] Fix PCI ROM mapping"). Link: https://lkml.org/lkml/2005/8/30/138 Signed-off-by: Bjorn Helgaas Reviewed-by: Gavin Shan Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman [sumits: minor fixup in rom.c for 4.4.y] Signed-off-by: Sumit Semwal Signed-off-by: Greg Kroah-Hartman --- drivers/pci/rom.c | 5 +++++ drivers/pci/setup-res.c | 6 ++++++ 2 files changed, 11 insertions(+) --- a/drivers/pci/rom.c +++ b/drivers/pci/rom.c @@ -31,6 +31,11 @@ int pci_enable_rom(struct pci_dev *pdev) if (!res->flags) return -1; + /* + * Ideally pci_update_resource() would update the ROM BAR address, + * and we would only set the enable bit here. But apparently some + * devices have buggy ROM BARs that read as zero when disabled. + */ pcibios_resource_to_bus(pdev->bus, ®ion, res); pci_read_config_dword(pdev, pdev->rom_base_reg, &rom_addr); rom_addr &= ~PCI_ROM_ADDRESS_MASK; --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -68,6 +68,12 @@ static void pci_std_update_resource(stru if (resno < PCI_ROM_RESOURCE) { reg = PCI_BASE_ADDRESS_0 + 4 * resno; } else if (resno == PCI_ROM_RESOURCE) { + + /* + * Apparently some Matrox devices have ROM BARs that read + * as zero when disabled, so don't update ROM BARs unless + * they're enabled. See https://lkml.org/lkml/2005/8/30/138. + */ if (!(res->flags & IORESOURCE_ROM_ENABLE)) return; Patches currently in stable-queue which might be from sumit.semwal@linaro.org are queue-4.4/pci-add-comments-about-rom-bar-updating.patch queue-4.4/acpi-blacklist-make-dell-latitude-3350-ethernet-work.patch queue-4.4/s390-zcrypt-introduce-cex6-toleration.patch queue-4.4/block-allow-write_same-commands-with-the-sg_io-ioctl.patch queue-4.4/pci-do-any-vf-bar-updates-before-enabling-the-bars.patch queue-4.4/x86-hyperv-handle-unknown-nmis-on-one-cpu-when-unknown_nmi_panic.patch queue-4.4/serial-8250_pci-detach-low-level-driver-during-pci-error-recovery.patch queue-4.4/xen-do-not-re-use-pirq-number-cached-in-pci-device-msi-msg-data.patch queue-4.4/pci-separate-vf-bar-updates-from-standard-bar-updates.patch queue-4.4/pci-ignore-bar-updates-on-virtual-functions.patch queue-4.4/pci-update-bars-using-property-bits-appropriate-for-type.patch queue-4.4/vfio-spapr-postpone-allocation-of-userspace-version-of-tce-table.patch queue-4.4/pci-don-t-update-vf-bars-while-vf-memory-space-is-enabled.patch queue-4.4/igb-workaround-for-igb-i210-firmware-issue.patch queue-4.4/pci-remove-pci_resource_bar-and-pci_iov_resource_bar.patch queue-4.4/pci-decouple-ioresource_rom_enable-and-pci_rom_address_enable.patch queue-4.4/acpi-blacklist-add-_rev-quirks-for-dell-precision-5520-and-3520.patch queue-4.4/igb-add-i211-to-i210-phy-workaround.patch queue-4.4/uvcvideo-uvc_scan_fallback-for-webcams-with-broken-chain.patch