On 2025/2/27 05:36, William McVicker wrote:
>> Every time this code is touched, it breaks. This is not even the only
>> breakage right now[1].
> You can find the Pixel 6/7/8/9 device trees on android.googlesource.com.
> You can see for zuma based devices (Pixel 9 for example) they have this [1]:
>
> &reserved_memory {
> #address-cells = <2>;
> #size-cells = <1>;
> vstream: vstream {
> compatible = "shared-dma-pool";
> reusable;
> size = <0x4800000>;
> alignment = <0x0 0x00010000>;
> alloc-ranges = <0x9 0x80000000 0x80000000>,
> <0x9 0x00000000 0x80000000>,
> <0x8 0x80000000 0x80000000>,
> <0x0 0x80000000 0x80000000>;
> };
>
> I understand this code is downstream, but as a general principle we shouldn't
> break backwards compatibilty.
this is not backward compatibility issue. it is a downstream bug instead.
normally, you need to write DTS according to relevant DT binding spec or
DT spec.
i can't access the link you shared due to my country's GFW.
does google kernel have extra binding spec about size of property
'alignment'?
IMO, downstream maintainers may needs to fix this issue by if the
upstream fix is picked up.
- alignment = <0x0 0x00010000>;
+ alignment = <0x00010000>;
actually, "The importance of getting code into the mainline" within
Documentation/process/1.Intro.rst encourages upstream your code to
avoid such issue.
