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@@ -5556,9 +5556,13 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
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u32 lnkcap2, lnkcap;
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/*
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- * PCIe r4.0 sec 7.5.3.18 recommends using the Supported Link
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- * Speeds Vector in Link Capabilities 2 when supported, falling
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- * back to Max Link Speed in Link Capabilities otherwise.
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+ * Link Capabilities 2 was added in PCIe r3.0, sec 7.8.18. The
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+ * implementation note there recommends using the Supported Link
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+ * Speeds Vector in Link Capabilities 2 when supported.
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+ *
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+ * Without Link Capabilities 2, i.e., prior to PCIe r3.0, software
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+ * should use the Supported Link Speeds field in Link Capabilities,
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+ * where only 2.5 GT/s and 5.0 GT/s speeds were defined.
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*/
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pcie_capability_read_dword(dev, PCI_EXP_LNKCAP2, &lnkcap2);
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if (lnkcap2) { /* PCIe r3.0-compliant */
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@@ -5574,16 +5578,10 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
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}
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pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
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- if (lnkcap) {
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- if (lnkcap & PCI_EXP_LNKCAP_SLS_16_0GB)
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- return PCIE_SPEED_16_0GT;
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- else if (lnkcap & PCI_EXP_LNKCAP_SLS_8_0GB)
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- return PCIE_SPEED_8_0GT;
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- else if (lnkcap & PCI_EXP_LNKCAP_SLS_5_0GB)
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- return PCIE_SPEED_5_0GT;
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- else if (lnkcap & PCI_EXP_LNKCAP_SLS_2_5GB)
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- return PCIE_SPEED_2_5GT;
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- }
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+ if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_5_0GB)
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+ return PCIE_SPEED_5_0GT;
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+ else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_2_5GB)
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+ return PCIE_SPEED_2_5GT;
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return PCI_SPEED_UNKNOWN;
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}
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