On 5/24/19 5:22 PM, Frank Rowand wrote: > On 5/24/19 2:53 PM, Saravana Kannan wrote: >> On Fri, May 24, 2019 at 10:49 AM Frank Rowand <frowand.list@xxxxxxxxx> wrote: >>> >>> On 5/23/19 6:01 PM, Saravana Kannan wrote: > > < snip > > >>> Another flaw with this method is that existing device trees >>> will be broken after the kernel is modified, because existing >>> device trees do not have the depends-on property. This breaks >>> the devicetree compatibility rules. >> >> This is 100% not true with the current implementation. I actually >> tested this. This is fully backwards compatible. That's another reason >> for adding depends-on and going by just what it says. The existing >> bindings were never meant to describe only mandatory dependencies. So >> using them as such is what would break backwards compatibility. > > Are you saying that an existing, already compiled, devicetree (an FDT) > can be used to boot a new kernel that has implemented this patch set? > > The new kernel will boot with the existing FDT that does not have > any depends-on properties? I overlooked something you said in the email I replied to. You said: "that depends-on becomes the source of truth if it exists and falls back to existing common bindings if "depends-on" isn't present" Let me go back to look at the patch series to see how it falls back to the existing bindings. > > -Frank >
