On 2021-08-30 10:58:09, Bjorn Andersson wrote: [...] > > > > > > Afaik these devices all boots off a boot.img, which means that it's > > > unlikely that a new kernel is installed on a device with an older DT. > > > None of them would boot mainline off the DT that shipped with the > > > original product. > > > > That was my understanding as well, DT overlays are a "new thing" afaik > > and most devices (at least all Sony's that I'm working with) use an > > appended DTB that's always in-sync with the kernel image. > > > > I think that with the introduction of DT overlays the system becomes > more flexible and as such more susceptible for bugs caused by unexpected > DT versions. Offtopic: We have some problems with this on newer Sony devices where the BL indeed tries to overlay this DTBO on the DT, which is usually a downstream DT not fitting on top of a mainline kernel+appended-DTB. The solution is to simply wipe DTBO, and afaik it should be fine to compile the overlay bits directly inside the appended-DTB anyway. Leads to unsuspecting problems at times, but it is manageable. > I think in practice the real issues comes when the DTB is delivered > separately (i.e. not by boot.img) or inbetween two kernel releases where > the Qualcomm tree might not be in sync with the driver tree. Dmitry sees this as a problem for msm8974 but I'm not familiar enough with the board. I take it this doesn't use appended DTBs then? > > > As such, if I pick this patch up as a fix for 5.15 you can respin the > > > other two patches and they can land in 5.16 and I would be surprised if > > > anyone will run into any issues with it. > > > > > > I.e. I've applied this patch. > > > > Sounds good, I'll leave this patch out from v2. Should it have a Fixes: > > tag to get backported too? > > > > Sounds good, I added to this: > > Fixes: 6969d1d9c615 ("ARM: dts: qcom-apq8064: Set 'cxo_board' as ref clock of the DSI PHY") Did the same on the v2 respin since it seems like those patches were incomplete without the driver change. > > Since most review seems to be in I'll respin v2 shortly with the > > addition of the "ref" clock to msm8974, that should probably get the > > same treatment (added to 5.15 fixes) then we can land this patchset in > > 5.16 (maybe without .name= fallback if Dmitry is okay with that). > > > > Sounds good. Sent the msm8974 patch separately and re-spun a v2. I haven't added the .name="xo" fallback yet while awaiting Dmitry to see if that counts as enough time for firmware to be delivered between kernel 5.15 and 5.16. - Marijn