On Wed, Sep 14, 2022 at 12:25:51PM +0100, Jon Hunter wrote: > > On 14/09/2022 12:18, Manivannan Sadhasivam wrote: > > On Wed, Sep 14, 2022 at 04:32:10PM +0530, Vidya Sagar wrote: > > > Agree with Mani. > > > Not all form factors support PRSNT pin (Ex:- M.2 Key-M form factor) and even > > > if the slot form factor supports PRSNT, it is not mandatory to have a GPIO > > > routed to the PRSNT pin of the slot. > > > > Right. > > > > > Also, since these are development platforms, we wouldn't want to keep > > > changing a controller's status in the DT, instead want to know the device's > > > presence/absence (by way of link up) looking at the log. > > > In my honest opinion, I don't think the absence of a device in the slot > > > should be treated as an error. > > > > > > > As I mentioned earlier, timeout can happen due to an issue with PHY layer > > also. In those cases, "dev_err()" is relevant. > > > > And I also agree that absence of the device should not be treated as an > > error. But my question is, if you know that the slot is going to be > > empty always, why cannot you just disable it in dts? > > I really don't think that makes sense from a usability perspective. You want > to allow users to connect PCI cards and for them to work without having to > update the DTB. I have plenty of open PCI slots on my PC and I would be a > bit upset if someone told me I need to update the PC firmware each time I > wanted to use a new slot. > My question was, "do you think the slot is going to be empty always". This can happen with slots exposed through a connector (not a PCIe one) and users would plug in add-on cards for accessing the slots. In those cases, the add-on specific devicetree can enable the PCIe instance and use it. But from your reply, I can infer that the slot is exposed on a standard PCIe connector and users would connect a PCIe device any time. Anyway, I don't strongly object the change and leave it to the maintainers to decide. Thanks, Mani > Jon > > -- > nvpublic
