On 11/28/12 02:10, Ben Hutchings wrote:

On Tue, 2012-11-27 at 17:32 +0000, Fujinaka, Todd wrote:

quoted

Forgive me if I'm being too repetitious as I think some of this has
been mentioned in the past.

We (and by we I mean the Ethernet part and driver) can only change the
advertised availability of a larger MaxPayloadSize. The size is
negotiated by both sides of the link when the link is established. The
driver should not change the size of the link as it would be poking at
registers outside of its scope and is controlled by the upstream
bridge (not us).

[...]

MaxPayloadSize (MPS) is not negotiated between devices but is programmed
by the system firmware (at least for devices present at boot - the
kernel may be responsible in case of hotplug).  You can use the kernel
parameter 'pci=pcie_bus_perf' (or one of several others) to set a policy
that overrides this, but no policy will allow setting MPS above the
device's MaxPayloadSizeSupported (MPSS).

Ben,

Unfortunately I'm using 3.0.x kernel and this is not included in the kernel.
So I'm trying to use ethtool modify it from eeprom to see if help or no.


Todd, I'll review all MaxPayload for all devices, but need to say if it mismatch,
customer could not modify it from BIOS for there was not entry at there, to
test it, we have to find how to verify if this is the root cause, so still 
need to find the offset in eeprom.

Thanks in advance,
Joe