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| author | David Daney | 2016-11-17 23:25:01 +0100 |
|---|---|---|
| committer | Bjorn Helgaas | 2016-12-08 21:44:22 +0100 |
| commit | e53f9a28bee35932a0ae4d2ec2784f55491ec6d3 (patch) | |
| tree | ef9e649c3cb4156ac6507fabd3f045c788cd8566 /drivers/pci/pcie/aspm.c | |
| parent | PCI/ASPM: Use permission-specific DEVICE_ATTR variants (diff) | |
| download | kernel-qcow2-linux-e53f9a28bee35932a0ae4d2ec2784f55491ec6d3.tar.gz kernel-qcow2-linux-e53f9a28bee35932a0ae4d2ec2784f55491ec6d3.tar.xz kernel-qcow2-linux-e53f9a28bee35932a0ae4d2ec2784f55491ec6d3.zip | |
PCI/ASPM: Don't retrain link if ASPM not possible
Some (defective) PCIe devices are not able to reliably do link retraining.
Check to see if ASPM is possible between link partners before configuring
common clocking, and doing the resulting link retraining. If ASPM is not
possible, there is no reason to risk losing access to a device due to an
unnecessary link retraining.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/pcie/aspm.c')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 3b14d9e85dee..17ac1dce3286 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -351,12 +351,26 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) return; } + /* Get upstream/downstream components' register state */ + pcie_get_aspm_reg(parent, &upreg); + child = list_entry(linkbus->devices.next, struct pci_dev, bus_list); + pcie_get_aspm_reg(child, &dwreg); + + /* + * If ASPM not supported, don't mess with the clocks and link, + * bail out now. + */ + if (!(upreg.support & dwreg.support)) + return; + /* Configure common clock before checking latencies */ pcie_aspm_configure_common_clock(link); - /* Get upstream/downstream components' register state */ + /* + * Re-read upstream/downstream components' register state + * after clock configuration + */ pcie_get_aspm_reg(parent, &upreg); - child = list_entry(linkbus->devices.next, struct pci_dev, bus_list); pcie_get_aspm_reg(child, &dwreg); /* |