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PCI/DPC: Quirk PIO log size for certain Intel Root Ports 

Some Root Ports on Intel Tiger Lake and Alder Lake systems support the RP
Extensions for DPC and the RP PIO Log registers but incorrectly advertise
an RP PIO Log Size of zero.  This means the kernel complains that:

  DPC: RP PIO log size 0 is invalid

and if DPC is triggered, the DPC driver will not dump the RP PIO Log
registers when it should.

This is caused by a BIOS bug and should be fixed the BIOS for future CPUs.

Add a quirk to set the correct RP PIO Log size for the affected Root Ports.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=209943
Link: https://lore.kernel.org/r/20220816102042.69125-1-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
This commit is contained in:
Mika Westerberg 2022-08-16 13:20:42 +03:00 committed by Bjorn Helgaas
parent 568035b01c
commit 5459c0b704
2 changed files with 46 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/pci/pcie/dpc.c
View File

@ -335,11 +335,16 @@ void pci_dpc_init(struct pci_dev *pdev)
return;
pdev->dpc_rp_extensions = true;
pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
pci_err(pdev, "RP PIO log size %u is invalid\n",
pdev->dpc_rp_log_size);
pdev->dpc_rp_log_size = 0;
/* Quirks may set dpc_rp_log_size if device or firmware is buggy */
if (!pdev->dpc_rp_log_size) {
pdev->dpc_rp_log_size =
(cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
pci_err(pdev, "RP PIO log size %u is invalid\n",
pdev->dpc_rp_log_size);
pdev->dpc_rp_log_size = 0;
}
}
}

36
drivers/pci/quirks.c
View File

@ -5956,3 +5956,39 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56b1, aspm_l1_acceptable_latency
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c0, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c1, aspm_l1_acceptable_latency);
#endif
#ifdef CONFIG_PCIE_DPC
/*
* Intel Tiger Lake and Alder Lake BIOS has a bug that clears the DPC
* RP PIO Log Size of the integrated Thunderbolt PCIe Root Ports.
*/
static void dpc_log_size(struct pci_dev *dev)
{
u16 dpc, val;
dpc = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
if (!dpc)
return;
pci_read_config_word(dev, dpc + PCI_EXP_DPC_CAP, &val);
if (!(val & PCI_EXP_DPC_CAP_RP_EXT))
return;
if (!((val & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8)) {
pci_info(dev, "Overriding RP PIO Log Size to 4\n");
dev->dpc_rp_log_size = 4;
}
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x461f, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x462f, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x463f, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x466e, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a23, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a25, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a27, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a29, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2b, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2d, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2f, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a31, dpc_log_size);
#endif