From: Jon Mason <jon.mason@broadcom.com>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC] PCI: Change default MPS behavior
Date: Tue, 6 Dec 2016 19:20:27 -0500 [thread overview]
Message-ID: <1481070027-9096-1-git-send-email-jon.mason@broadcom.com> (raw)
Not all systems have a BIOS or firmware to preconfigure the PCIE MPS
prior to Linux booting. Without any firmware to pre-setup the MPS, the
PCIE_BUS_DEFAULT will simply set everything to 0 (128b). This behavior
causes these systems to have non-optimal MPS values. To get around this
issue, change the default value of pcie_bus_config to be PCIE_BUS_SAFE.
This configures all systems to use better values for the MPS, at the
expense of any potential HW errata that might not like being changed.
Signed-off-by: Jon Mason <jon.mason@broadcom.com>
---
drivers/pci/pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index ba34907..94d574e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -88,7 +88,7 @@ unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
#define DEFAULT_HOTPLUG_BUS_SIZE 1
unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
-enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT;
+enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_SAFE;
/*
* The default CLS is used if arch didn't set CLS explicitly and not
--
2.7.4
next reply other threads:[~2016-12-07 0:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 0:20 Jon Mason [this message]
2016-12-07 19:15 ` [RFC] PCI: Change default MPS behavior Keith Busch
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