From: Shuai Xue Date: Wed, 11 Feb 2026 12:46:24 +0000 (+0800) Subject: PCI/AER: Clear only error bits in PCIe Device Status X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8aeea1bf3c80cc87983689e0118770e019bd4f3;p=thirdparty%2Flinux.git PCI/AER: Clear only error bits in PCIe Device Status Currently, pcie_clear_device_status() clears the entire PCIe Device Status register (PCI_EXP_DEVSTA) by writing back the value read from the register, which affects not only the error status bits but also other writable bits. According to PCIe r7.0, sec 7.5.3.5, this register contains: - RW1C error status bits (CED, NFED, FED, URD at bits 0-3): These are the four error status bits that need to be cleared. - Read-only bits (AUXPD at bit 4, TRPND at bit 5): Writing to these has no effect. - Emergency Power Reduction Detected (bit 6): A RW1C non-error bit introduced in PCIe r5.0 (2019). This is currently the only writable non-error bit in the Device Status register. Unconditionally clearing this bit can interfere with other software components that rely on this power management indication. - Reserved bits (RsvdZ): These bits are required to be written as zero. Writing 1s to them (as the current implementation may do) violates the specification. To prevent unintended side effects, modify pcie_clear_device_status() to only write 1s to the four error status bits (CED, NFED, FED, URD), leaving the Emergency Power Reduction Detected bit and reserved bits unaffected. Fixes: ec752f5d54d7 ("PCI/AER: Clear device status bits during ERR_FATAL and ERR_NONFATAL") Suggested-by: Lukas Wunner Signed-off-by: Shuai Xue Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Lukas Wunner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260211124624.49656-1-xueshuai@linux.alibaba.com --- diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 8479c2e1f74f1..8e3e4e24c9096 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2241,10 +2241,9 @@ EXPORT_SYMBOL_GPL(pci_set_pcie_reset_state); #ifdef CONFIG_PCIEAER void pcie_clear_device_status(struct pci_dev *dev) { - u16 sta; - - pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &sta); - pcie_capability_write_word(dev, PCI_EXP_DEVSTA, sta); + pcie_capability_write_word(dev, PCI_EXP_DEVSTA, + PCI_EXP_DEVSTA_CED | PCI_EXP_DEVSTA_NFED | + PCI_EXP_DEVSTA_FED | PCI_EXP_DEVSTA_URD); } #endif