Hi Wim, On 7/7/2017 10:53 AM, Sinan Kaya wrote: > According to extended tags ECN document, all PCIe receivers are expected > to support extended tags support. It should be safe to enable extended > tags on endpoints without checking compatibility. > > This assumption seems to be working fine except for the legacy systems. > The ECN has been written against PCIE spec version 2.0. Therefore, we need > to exclude all version 1.0 devices from this change as there is HW out > there that can't handle extended tags. > > Note that the default value of Extended Tags Enable bit is implementation > specific. Therefore, we are clearing the bit by default when incompatible > HW is found without assuming that value is zero. > > Reported-by: Wim ten Have <wim.ten.have@xxxxxxxxxx> > Link: https://pcisig.com/sites/default/files/specification_documents/ECN_Extended_Tag_Enable_Default_05Sept2008_final.pdf > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1467674 > Fixes: 60db3a4d8cc9 ("PCI: Enable PCIe Extended Tags if supported") > Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx> > --- Can you also give this a spin? I don't have a system with v1 PCIe bridges. I only tested v2 and later code path. I tried to address Jike Song concerns on this version and removed your tested-by since the code changed. Sinan -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
