On Lenovo X1 Carbon Gen 7/8 devices, when a platform enables a policy to distrust removable PCI devices, the build-in USB-C ports stop working at all. This happens because these X1 Carbon models have a unique feature; a Thunderbolt controller that is discrete from the SoC. The software sees this controller, and incorrectly assumes it is a removable PCI device, even though it is fixed to the computer and is wired to the computer's own USB-C ports. Relabel all the components of the JHL6540 controller as DEVICE_FIXED, and where applicable, external_facing. Ensure that the security policy to distrust external PCI devices works as intended, and that the device's USB-C ports are able to enumerate even when the policy is enabled. Signed-off-by: Esther Shimanovich <eshimanovich@xxxxxxxxxxxx> --- Changes in v3: - removed redundant dmi check, as the subsystem vendor check is sufficient - switched to PCI_VENDOR_ID_LENOVO instead of hex code - Link to v2: https://lore.kernel.org/r/20231219-thunderbolt-pci-patch-4-v2-1-ec2d7af45a9b@xxxxxxxxxxxx Changes in v2: - nothing new, v1 was just a test run to see if the ASCII diagram would be rendered properly in mutt and k-9 - for folks using gmail, make sure to select "show original" on the top right, as otherwise the diagram will be garbled by the standard non-monospace font - Link to v1: https://lore.kernel.org/r/20231219-thunderbolt-pci-patch-4-v1-1-4e8e3773f0a9@xxxxxxxxxxxx --- drivers/pci/quirks.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index ea476252280a..3e6e5fa94d99 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -3873,6 +3873,112 @@ DECLARE_PCI_FIXUP_SUSPEND_LATE(PCI_VENDOR_ID_INTEL, quirk_apple_poweroff_thunderbolt); #endif +/* + * On most ThinkPad Carbon 7/8s, JHL6540 Thunderbolt 3 bridges are set + * incorrectly as DEVICE_REMOVABLE despite being built into the device. + * This is the side effect of a unique hardware configuration. + * + * Normally, Thunderbolt functionality is integrated to the SoC and + * its root ports. + * + * Most devices: + * root port --> USB-C port + * + * But X1 Carbon Gen 7/8 uses Whiskey Lake and Comet Lake SoC, which + * don't come with Thunderbolt functionality. Therefore, a discrete + * Thunderbolt Host PCI controller was added between the root port and + * the USB-C port. + * + * Thinkpad Carbon 7/8s + * (w/ Whiskey Lake and Comet Lake SoC): + * root port --> JHL6540 --> USB-C port + * + * Because the root port is labeled by FW as "ExternalFacingPort", as + * required by the DMAR ACPI spec, the JHL6540 chip is inaccurately + * labeled as DEVICE_REMOVABLE by the kernel pci driver. + * Therefore, the built-in USB-C ports do not enumerate when policies + * forbidding external pci devices are enforced. + * + * This fix relabels the pci components in the built-in JHL6540 chip as + * DEVICE_FIXED, ensuring that the built-in USB-C ports always enumerate + * properly as intended. + * + * This fix also labels the external facing components of the JHL6540 as + * external_facing, so that the pci attach policy works as intended. + * + * The ASCII diagram below describes the pci layout of the JHL6540 chip. + * + * Root Port + * [8086:02b4] or [8086:9db4] + * | + * JHL6540 Chip + * __________________________________________________ + * | Bridge | + * | PCI ID -> [8086:15d3] | + * | DEVFN -> (00) | + * | _________________|__________________ | + * | | | | | | + * | Bridge Bridge Bridge Bridge | + * | [8086:15d3] [8086:15d3] [8086:15d3] [8086:15d3] | + * | (00) (08) (10) (20) | + * | | | | | | + * | NHI | USB Controller | | + * | [8086:15d2] | [8086:15d4] | | + * | (00) | (00) | | + * | |___________| |___________| | + * |____________|________________________|____________| + * | | + * USB-C Port USB-C Port + * + * + * Based on what a JHL6549 pci component's pci id, subsystem device id + * and devfn are, we can infer if it is fixed and if it faces a usb port; + * which would mean it is external facing. + * This quirk uses these values to identify the pci components and set the + * properties accordingly. + */ +static void carbon_X1_fixup_relabel_alpine_ridge(struct pci_dev *dev) +{ + /* Is this JHL6540 PCI component embedded in a Lenovo device? */ + if (dev->subsystem_vendor != PCI_VENDOR_ID_LENOVO) + return; + + /* Is this JHL6540 PCI component embedded in an X1 Carbon Gen 7/8? */ + if (dev->subsystem_device != 0x22be && // Gen 8 + dev->subsystem_device != 0x2292) { // Gen 7 + return; + } + + dev_set_removable(&dev->dev, DEVICE_FIXED); + + /* Not all 0x15d3 components are external facing */ + if (dev->device == 0x15d3 && + dev->devfn != 0x08 && + dev->devfn != 0x20) { + return; + } + + dev->external_facing = true; +} + +/* + * We also need to relabel the root port as a consequence of changing + * the JHL6540's PCIE hierarchy. + */ +static void carbon_X1_fixup_rootport_not_removable(struct pci_dev *dev) +{ + if (!dmi_match(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 7th") && + !dmi_match(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon Gen 8")) + return; + + dev->external_facing = false; +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15d3, carbon_X1_fixup_relabel_alpine_ridge); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15d2, carbon_X1_fixup_relabel_alpine_ridge); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x15d4, carbon_X1_fixup_relabel_alpine_ridge); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x02b4, carbon_X1_fixup_rootport_not_removable); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x9db4, carbon_X1_fixup_rootport_not_removable); + /* * Following are device-specific reset methods which can be used to * reset a single function if other methods (e.g. FLR, PM D0->D3) are --- base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86 change-id: 20231219-thunderbolt-pci-patch-4-ede71cb833c4 Best regards, -- Esther Shimanovich <eshimanovich@xxxxxxxxxxxx>
