Messages in this thread Patch in this message | | | From | Sinan Kaya <> | Subject | [PATCH] PCI: enable extended tags support for PCIe endpoints | Date | Sat, 24 Sep 2016 22:10:34 -0400 |
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Each PCIe device can issue up to 32 transactions at a time by default. Each transaction is tracked by a tag number on the bus. 32 outstanding transactions is not enough for some performance critical applications especially when a lot of small sized frames are transmitted.
Extended tags support increases this number to 256. Devices not supporting extended tags tie-off this field to 0. According to ECN, it is safe to enable this feature for all PCIe endpoints.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org> --- drivers/pci/probe.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 93f280d..2424f38 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1505,12 +1505,19 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp) */ } +static int pci_configure_extended_tags(struct pci_dev *dev) +{ + return pcie_capability_set_word(dev, PCI_EXP_DEVCTL, + PCI_EXP_DEVCTL_EXT_TAG); +} + static void pci_configure_device(struct pci_dev *dev) { struct hotplug_params hpp; int ret; pci_configure_mps(dev); + pci_configure_extended_tags(dev); memset(&hpp, 0, sizeof(hpp)); ret = pci_get_hp_params(dev, &hpp); -- 1.9.1
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