[linux-nvidia-6.18-next] Cherry-pick detected missing patch from Vera#452
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ltrager wants to merge 1 commit into
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[linux-nvidia-6.18-next] Cherry-pick detected missing patch from Vera#452ltrager wants to merge 1 commit into
ltrager wants to merge 1 commit into
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Per CXL r3.1, sec 8.1.5.2, the Secondary Bus Reset (SBR) bit in the Bridge Control register of a CXL port has no effect unless the "Unmask SBR" bit in the Port Control Extensions Register is set. After b1956e2 ("PCI/CXL: Fail bus reset if upstream CXL Port has SBR masked"), Linux checks the "Unmask SBR" bit in pci_reset_bus_function(). But when probe==true, it previously returned 0, incorrectly indicating that SBR is a viable reset method for the device. As a result, "bus" is listed in the device's "reset_method" attribute even though the hardware is incapable of performing it. If a user writes "bus" to "reset_method" or triggers a reset that falls back to SBR, the operation fails with "write error: Inappropriate ioctl for device". If the link is operating in CXL mode (pcie_is_cxl()), return -ENOTTY immediately unless "Unmask SBR" is set, regardless of the probe argument. This ensures that "bus" is not advertised in "reset_methods" when the hardware prevents it, improving clarity for users and aligning the sysfs capability report with actual hardware behavior. Signed-off-by: Vidya Sagar <vidyas@nvidia.com> [bhelgaas: commit log, use pcie_is_cxl()] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://patch.msgid.link/20260225133801.30231-1-vidyas@nvidia.com (cherry picked from commit 702c1d5) Signed-off-by: Lee Trager <ltrager@nvidia.com>
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Boro reviewSummaryNo issues found across the reviewed commits. Findings: no problems found Latest watcher review: open review Head: This comment is maintained by nv-pr-bot. It is updated when the GitHub watcher publishes a newer review. |
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Only 1 patch listed for Vera is not currently applied to 6.18. All other patches, including SAUCE patches, are applied.
Unable to test this as I don't have access to a host with CXL. However the patch is already upstream and pretty simple.