On Wed, Jul 21, 2021 at 01:02:20PM +0300, Serge Semin wrote: > Hi Greg, > @Krzysztof, @Rob, please join the discussion so to finally get done > with the concerned issue. > > On Wed, Jul 21, 2021 at 09:38:54AM +0200, Greg Kroah-Hartman wrote: > > On Wed, Jul 14, 2021 at 03:48:07PM +0300, Serge Semin wrote: > > > Hello John, > > > > > > On Tue, Jul 13, 2021 at 05:07:00PM -0700, John Stultz wrote: > > > > On Tue, Oct 20, 2020 at 5:10 AM Serge Semin > > > > <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > In accordance with the DWC USB3 bindings the corresponding node > > > > > name is suppose to comply with the Generic USB HCD DT schema, which > > > > > requires the USB nodes to have the name acceptable by the regexp: > > > > > "^usb(@.*)?" . Make sure the "snps,dwc3"-compatible nodes are correctly > > > > > named. > > > > > > > > > > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> > > > > > > > > > > > I know folks like to ignore this, but this patch breaks AOSP on db845c. :( > > > > > > Sorry to hear that. Alas there is no much can be done about it. > > > > Yes there is, we can revert the change. We do not break existing > > configurations, sorry. > > By reverting this patch we'll get back to the broken dt-bindings > since it won't comply to the current USB DT-nodes requirements > which at this state well describe the latest DT spec: > https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.3 > Thus the dtbs_check will fail for these nodes. > > Originally this whole patchset was connected with finally getting the > DT-node names in order to comply with the standard requirement and it > was successful mostly except a few patches which still haven't been > merged in. > > Anyway @Krzysztof has already responded to the complain regarding this > issue here: > https://lore.kernel.org/lkml/20201221210423.GA2504@kozik-lap/ > but noone cared to respond on his reasonable questions in order to > get to a suitable solution for everyone. Instead we are > getting another email with the same request to revert the changes. > Here is the quote from the Krzysztof email so we could continue the > discussion: > > On Mon, 21 Dec 2020 13:04:27 -0800 (PST), Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > > On Mon, Dec 21, 2020 at 12:24:11PM -0800, John Stultz wrote: > > > On Sat, Dec 19, 2020 at 3:06 AM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > > > > ... > > > > > > > > The node names are not part of an ABI, are they? I expect only > > > > compatibles and properties to be stable. If user-space looks for > > > > something by name, it's a user-space's mistake. Not mentioning that you > > > > also look for specific address... Imagine remapping of addresses with > > > > ranges (for whatever reason) - AOSP also would be broken? Addresses are > > > > definitely not an ABI. > > > > > > Though that is how it's exported through sysfs. > > > > The ABI is the format of sysfs file for example in /sys/devices. However > > the ABI is not the exact address or node name of each device. > > > > > In AOSP it is then used to setup the configfs gadget by writing that > > > value into /config/usb_gadget/g1/UDC. > > > > > > Given there may be multiple controllers on a device, or even if its > > > just one and the dummy hcd driver is enabled, I'm not sure how folks > > > reference the "right" one without the node name? > > > > I think it is the same type of problem as for all other subsystems, e.g. > > mmc, hwmon/iio. They usually solve it either with aliases or with > > special property with the name/label. > > > > > I understand the fuzziness with sysfs ABI, and I get that having > > > consistent naming is important, but like the eth0 -> enp3s0 changes, > > > it seems like this is going to break things. > > > > One could argue whether interface name is or is not ABI. But please tell > > me how the address of a device in one's representation (for example DT) > > is a part of a stable interface? > > > > > Greg? Is there some better way AOSP should be doing this? > > > > If you need to find specific device, maybe go through the given bus and > > check compatibles? > > > > Best regards, > > Krzysztof > > So the main question is how is the DT-node really connected with ABI > and is supposed to be stable in that concern? > > As I see it even if it affects the configfs node name, then we may > either need to break that connection and somehow deliver DT-node-name > independent interface to the user-space or we have no choice but to > export the node with an updated name and ask of user-space to deal > with it. In both suggested cases the DT-node name will still conform > to the USB-node name DT spec. Currently we are at the second one. I really do not care what you all decide on, but you CAN NOT break existing working systems, sorry. That is why I have reverted this change in my tree and will send it to Linus soon. thanks, greg k-h
