diff options
| author | Yijing Wang <wangyijing@huawei.com> | 2013-08-26 10:33:06 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2013-08-26 22:49:28 +0200 |
| commit | 5895af79158a55562753f7f05762f3bd766d32b9 (patch) | |
| tree | 39eecfd0c9fa8c4963ec081ea171977e05b5b0b9 /drivers/pci/probe.c | |
| parent | PCI: Fix MPS peer-to-peer DMA comment syntax (diff) | |
| download | linux-5895af79158a55562753f7f05762f3bd766d32b9.tar.xz linux-5895af79158a55562753f7f05762f3bd766d32b9.zip | |
PCI: Warn if unsafe MPS settings detected
If a BIOS configures MPS incorrectly, devices may not work normally.
For example, if a bridge has MPS set larger than an endpoint below it,
the endpoint may discard packets.
To help diagnose this issue, print a warning if we find an endpoint
MPS setting different than that of the upstream bridge.
[bhelgaas: changelog, "bridge" temporary, warning text]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60799
Reported-by: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jon Mason <jdmason@kudzu.us>
Diffstat (limited to 'drivers/pci/probe.c')
| -rw-r--r-- | drivers/pci/probe.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 94c5a77ce853..cd5c4acb5367 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1582,6 +1582,22 @@ static void pcie_write_mrrs(struct pci_dev *dev) "with pci=pcie_bus_safe.\n"); } +static void pcie_bus_detect_mps(struct pci_dev *dev) +{ + struct pci_dev *bridge = dev->bus->self; + int mps, p_mps; + + if (!bridge) + return; + + mps = pcie_get_mps(dev); + p_mps = pcie_get_mps(bridge); + + if (mps != p_mps) + dev_warn(&dev->dev, "Max Payload Size %d, but upstream %s set to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n", + mps, pci_name(bridge), p_mps); +} + static int pcie_bus_configure_set(struct pci_dev *dev, void *data) { int mps, orig_mps; @@ -1589,6 +1605,11 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data) if (!pci_is_pcie(dev)) return 0; + if (pcie_bus_config == PCIE_BUS_TUNE_OFF) { + pcie_bus_detect_mps(dev); + return 0; + } + mps = 128 << *(u8 *)data; orig_mps = pcie_get_mps(dev); @@ -1616,9 +1637,6 @@ void pcie_bus_configure_settings(struct pci_bus *bus) if (!pci_is_pcie(bus->self)) return; - if (pcie_bus_config == PCIE_BUS_TUNE_OFF) - return; - /* FIXME - Peer to peer DMA is possible, though the endpoint would need * to be aware of the MPS of the destination. To work around this, * simply force the MPS of the entire system to the smallest possible. |