On Mon, Jul 26, 2021 at 10:37 PM Rob Herring [off-list ref] wrote:

On Mon, Jul 26, 2021 at 9:54 AM Arnd Bergmann [off-list ref] wrote:

quoted

On Mon, Jul 26, 2021 at 4:57 PM Rob Herring [off-list ref] wrote:

quoted

On Sun, Jul 25, 2021 at 10:52 PM Viresh Kumar [off-list ref] wrote:

quoted

+    description: |
+      Exactly one node describing the virtio device. The name of the node isn't
+      significant but its phandle can be used to by a user of the virtio device.
+
+  compatible:
+    pattern: "^virtio,[0-9a-f]+$"

DID is only 4 chars? If so, "^virtio,[0-9a-f]{1,4}$"

Any opinion on whether this should have any namespace prefix (or infix, I guess)
after "virtio,"?

I previously suggested making it "virtio,device[0-9a-f]{1,4}$", which would
make it clearer that the following digits are the device ID rather
than something
else we might define in the future. Viresh picked this version because it's
somewhat more consistent with other subsystems.

I'm fine either way, though I do find just a number a bit strange. So
I'd lean toward adding 'device' or even just a 'd'.

I don't think just 'd' would be a good idea since it is indistinguishable from
a hexadecimal character. 'dev' would work though.

BTW, what happens if/when the device protocol is rev'ed? A new DID or
is there a separate revision that's discoverable?

This should normally be done using feature bits that are negotiated
between the two sides, and if only one side can do it, they use the
old revision.

There could be a new device ID but I don't think that has happened so far.

       Arnd