From 425c1b223dac456d00a61fd6b451b6d1cf00d065 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Tue, 17 Dec 2013 16:43:51 -0700 Subject: PCI: Add Virtual Channel to save/restore support While we don't really have any infrastructure for making use of VC support, the system BIOS can configure the topology to non-default VC values prior to boot. This may be due to silicon bugs, desire to reserve traffic classes, or perhaps just BIOS bugs. When we reset devices, the VC configuration may return to default values, which can be incompatible with devices upstream. For instance, Nvidia GRID cards provide a PCIe switch and some number of GPUs, all supporting VC. The power-on default for VC is to support TC0-7 across VC0, however some platforms will only enable TC0/VC0 mapping across the topology. When we do a secondary bus reset on the downstream switch port, the GPU is reset to a TC0-7/VC0 mapping while the opposite end of the link only enables TC0/VC0. If the GPU attempts to use TC1-7, it fails. This patch attempts to provide complete support for VC save/restore, even beyond the minimally required use case above. This includes save/restore and reload of the arbitration table, save/restore and reload of the port arbitration tables, and re-enabling of the channels for VC, VC9, and MFVC capabilities. Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 8f2be7ec705c..508e560b7d2a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -984,6 +984,8 @@ pci_save_state(struct pci_dev *dev) return i; if ((i = pci_save_pcix_state(dev)) != 0) return i; + if ((i = pci_save_vc_state(dev)) != 0) + return i; return 0; } @@ -1046,6 +1048,7 @@ void pci_restore_state(struct pci_dev *dev) /* PCI Express register must be restored first */ pci_restore_pcie_state(dev); pci_restore_ats_state(dev); + pci_restore_vc_state(dev); pci_restore_config_space(dev); @@ -2118,6 +2121,8 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev) if (error) dev_err(&dev->dev, "unable to preallocate PCI-X save buffer\n"); + + pci_allocate_vc_save_buffers(dev); } void pci_free_cap_save_buffers(struct pci_dev *dev) -- cgit v1.2.1