Re: [PATCH RFC 0/2] Generate device tree node for pci devicesgain,

Clément Léger
2022-10-13T08:01:32Z

Le Thu, 13 Oct 2022 01:05:26 -0500,
Frank Rowand <frowand.list@gmail.com> a écrit :

> > This would also require two different descriptions of the same card
> > (for ACPI and device-tree) and would require the final user to create a
> > specific overlay for its device based on the PCI slots the card is
> > plugged in.
>
> One of the many missing pieces of overlay support. There have been several
> discussion of how to describe a "socket" in a device tree that a device
> could be plugged into, where a single device tree subtree .dtb could be
> relocated to one or more different socket locations. Thus in this
> case a single overlay could be relocated to various PCI slots.
>
> I don't expect be getting involved in any future efforts around sockets
> (see my following comment for why).
>
> >
> > The solution we proposed (Lizhi and I) allows to overcome these
> > problems and is way easier to use. Fixing the potential bugs that might
> > exists in the overlay layer seems a way better idea that just pushing
>
> It is not potential bugs. The current run time overlay implementation is
> proof of concept quality and completeness. It is not production ready.
>
> I got an opportunity for early retirement a couple of weeks ago. My first
> inclination was to continue the same level of device tree maintainership,
> but I am quickly realizing that there are other activities that I would
> like to devote my time and energy to. I will continue to support Rob with
> minor patch reviews and testing, and potentially finishing up some
> improvements to unittest. On the other hand, bringing run time overlay
> support to product quality would be a major investment of my time that I
> am not willing to continue.

Hi Frank,

This explains your position on the overlay support and I can
certainly understand it ! Regarding the fact that it would enter
"production", the devices we are talking about are not really
widespread yet? This would be a good opportunity to gather feedback
early and improve the support gradually. We could probably even be able
to support improvements in the overlay code if needed I guess.

Thanks for your honest answer,

Clément

>
> So I am leaving major overlay issues in the capable hands of Rob. I may
> chime in from time to time when I can do so without requiring too much of
> my time.
>
> -Frank
>
> > that away to the bootloader level. Moreover, this kind of devices is
> > likely to be more common with the increasing popularity of FPGA and a
> > proper solution must be found.
> >

--
Clément Léger,
Embedded Linux and Kernel engineer at Bootlin