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[0/2] Augment device matching its upstream Root Port's MPS logic

Message ID 20180813181931.105655.22182.stgit@tak.stowe (mailing list archive)
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Series Augment device matching its upstream Root Port's MPS logic | expand

Message

Myron Stowe Aug. 13, 2018, 6:19 p.m. UTC
In commit 27d868b5e6cf ("PCI: Set MPS to match upstream bridge") Keith made
sure every device's MPS setting matched its upstream bridge, making it more
likely that a hot-added devices would work in a system with an optimized MPS
configuration.

This series augments Keith's approach to include tuning down a Root Port's
MPS setting in the case where a hot-added device is not capable of matching
it (see: [1]).

Testing by Dongdong exposed a bug with the logic including Virtual Functions
(VFs).  VFs should not be included so a pre-cursor patch, 1/2, was added to
cover such.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=200527

Myron Stowe (2):
      PCI: Skip MPS logic for Virtual Functions (VFs)
      PCI: Match Root Port's MPS to endpoint's MPSS as necessary


 drivers/pci/probe.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

--

Comments

Bjorn Helgaas Aug. 14, 2018, 2:18 p.m. UTC | #1
On Mon, Aug 13, 2018 at 12:19:31PM -0600, Myron Stowe wrote:
> In commit 27d868b5e6cf ("PCI: Set MPS to match upstream bridge") Keith made
> sure every device's MPS setting matched its upstream bridge, making it more
> likely that a hot-added devices would work in a system with an optimized MPS
> configuration.
> 
> This series augments Keith's approach to include tuning down a Root Port's
> MPS setting in the case where a hot-added device is not capable of matching
> it (see: [1]).
> 
> Testing by Dongdong exposed a bug with the logic including Virtual Functions
> (VFs).  VFs should not be included so a pre-cursor patch, 1/2, was added to
> cover such.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=200527
> 
> Myron Stowe (2):
>       PCI: Skip MPS logic for Virtual Functions (VFs)
>       PCI: Match Root Port's MPS to endpoint's MPSS as necessary
> 
> 
>  drivers/pci/probe.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)

Applied to pci/enumeration for v4.19, thanks!