[PATCH v7 0/2] PCI: Configure Root Port MPS during host probing

[Niklas Cassel]

On Mon, Jun 22, 2026 at 12:14:48PM -0500, Bjorn Helgaas wrote:
> On Fri, Jun 19, 2026 at 11:29:39PM +0800, Hans Zhang wrote:
> > On 5/6/26 22:00, Manivannan Sadhasivam wrote:
> > > On Fri, Nov 28, 2025 at 01:09:06AM +0800, Hans Zhang wrote:
> > > > Current PCIe initialization exhibits a key optimization gap: Root Ports
> > > > may operate with non-optimal Maximum Payload Size (MPS) settings. While
> > > > downstream device configuration is handled during bus enumeration, Root
> > > > Port MPS values inherited from firmware or hardware defaults often fail
> > > > to utilize the full capabilities supported by controller hardware. This
> > > > results in suboptimal data transfer efficiency throughout the PCIe
> > > > hierarchy.
> > > > 
> > > > This patch series addresses this by:
> > > > 
> > > > 1. Core PCI enhancement (Patch 1):
> > > > - Proactively configures Root Port MPS during host controller probing
> > > > - Sets initial MPS to hardware maximum (128 << dev->pcie_mpss)
> > > > - Conditional on PCIe bus tuning being enabled (PCIE_BUS_TUNE_OFF unset)
> > > >    and not in PCIE_BUS_PEER2PEER mode (which requires default 128 bytes)
> > > > - Maintains backward compatibility via PCIE_BUS_TUNE_OFF check
> > > > - Preserves standard MPS negotiation during downstream enumeration
> > > > 
> > > > 2. Driver cleanup (Patch 2):
> > > > - Removes redundant MPS configuration from Meson PCIe controller driver
> > > > - Functionality is now centralized in PCI core
> > > > - Simplifies driver maintenance long-term
> > > > 
> > > 
> > > For the series,
> > > 
> > > Reviewed-by: Manivannan Sadhasivam <mani at kernel.org>
> > > 
> > > Bjorn: Could you please take a look? This series has been floating for a
> > > while...
> > 
> > Hello Bjorn,
> > 
> > Any chance for this series to be applied?
> 
> It's too late for v7.2; we're already more than halfway through the
> merge window.  We can look again for v7.3 after v7.2-rc1.

ping


Kind regards,
Niklas