On Fri, 12 Nov 2021 18:12:49 +0100 Pali Rohár <pali@xxxxxxxxxx> wrote: > On Friday 12 November 2021 10:30:01 Rob Herring wrote: > > On Fri, Nov 12, 2021 at 9:32 AM Pali Rohár <pali@xxxxxxxxxx> wrote: > > > > > > On Friday 12 November 2021 09:25:20 Rob Herring wrote: > > > > On Sun, Oct 31, 2021 at 04:07:05PM +0100, Marek Behún wrote: > > > > > + If present, this property specifies slot power limit in milliwatts. Host > > > > > + drivers can parse this property and use it for programming Root Port or host > > > > > + bridge, or for composing and sending PCIe Set_Slot_Power_Limit messages > > > > > + through the Root Port or host bridge when transitioning PCIe link from a > > > > > + non-DL_Up Status to a DL_Up Status. > > > > > > > > If your slots are behind a switch, then doesn't this apply to any bridge > > > > port? > > > > > > The main issue here is that pci.txt (and also scheme on github) is > > > mixing host bridge and root ports into one node. This new property > > > should be defined at the same place where is supports-clkreq or > > > reset-gpios, as it belongs to them. > > > > Unfortunately that ship has already sailed. So we can split things up, > > but we still have to allow for the existing cases. I'm happy to take > > changes splitting up pci-bus.yaml to 2 or 3 schemas (host bridge, > > root-port, and PCI(e)-PCI(e) bridge?). > > Well, no problem. I just need to know how you want to handle backward > compatibility definitions in YAML. Because it is possible via versioning > (like in JSONSchema-like structures in OpenAPI versioning) or via > deprecated attributes or via defining two schemas (one strict and one > loose)... There are lot of options and I saw all these options in > different projects which use YAML or JSON. > > I did not know about github repository, I always looked at schemas and > definitions only in linux kernel tree and external files which were > mentioned in kernel tree. > > Something I wrote in my RFC email, but I wrote this email patch... > https://lore.kernel.org/linux-pci/20211023144252.z7ou2l2tvm6cvtf7@pali/ New kernel should always work with old device-tree. But does also new device-tree need to work with old kernels? Marek
