Re: [PATCH v4 1/4] PCI: Add debugfs support for exposing PTM context

From: Manivannan Sadhasivam
Date: Sat May 10 2025 - 02:21:11 EST


On Mon, May 05, 2025 at 01:37:14PM -0500, Bjorn Helgaas wrote:
> On Mon, May 05, 2025 at 07:54:39PM +0530, Manivannan Sadhasivam wrote:
> > Precision Time Management (PTM) mechanism defined in PCIe spec r6.0,
> > sec 6.21 allows precise coordination of timing information across multiple
> > components in a PCIe hierarchy with independent local time clocks.
> >
> > PCI core already supports enabling PTM in the root port and endpoint
> > devices through PTM Extended Capability registers. But the PTM context
> > supported by the PTM capable components such as Root Complex (RC) and
> > Endpoint (EP) controllers were not exposed as of now.
>
> IIUC, the PCIe spec defines the PTM link protocol in terms of these
> timestamps, but it does not provide any visibility of them to
> software, so any visibility is device-specific. I think it's worth
> mentioning something to this effect.
>

Added this info while applying the series, thanks!

- Mani

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