On Tue, Dec 06, 2016 at 07:20:27PM -0500, Jon Mason wrote: > 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. Wouldn't it be better to provide the kernel parameter to override the default on such platforms? The PCIE_BUS_SAFE sets the MPS to the lowest common denominator below the root port, which may be less optimal than the default behavior for hot plug. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
