Just one additional bit of info regarding the purpose of vc4-fkms-v3d being in Core 18 in the first place:
I'm not 100% sure of the reason it was there, but it's been since before Core 18, so I was loathe to remove something that users might be relying upon. As to what the overlay actually does: it implements "fake" KMS (hence the fkms in the name) by having the ARM core request (via the mailbox) that the GPU carry out the required operations. This is in contrast to the "proper" KMS overlay (vc4-kms-v3d) which isn't currently recommended because it leaves the ARM in full control of the GPU registers, which breaks certain other bits of the GPU firmware (notably the camera module cannot operate with the latter overlay at this time). The FKMS overlay is likely used by several graphical applications (e.g. it's near impossible to run a desktop on the Pi without it ... not that that's something anyone would sensibly try on a 3A+) so I was left with a choice of "which thing do you want to break today?": 1) Leave the fkms overlay in, breaking boot for the 3A+ but with a relatively simple workaround. 2) Remove the fkms overlay, permitting boot on all models but likely breaking several existing graphical applications on Core, again with a relatively simple workaround (add the overlay line back in). My judgment was that the 3A+ is quite a rare beast with relatively esoteric use-cases (it's primarily used either where someone needs the reduced weight, e.g. drones, or where someone wants the absolute lowest cost possible although that niche is arguably better served by the compute modules which come with their own storage), so the former option would likely break less people's experiences out of the box. @pwlars - interesting observation on the pi2. I can't say I'd seriously tested Core on there. I wonder if the CMA allocation of the overlay can be adjusted and whether that would make a difference. I had previously tried removing the ",cma-256" parameter and noted it made no difference, but I don't recall testing alternatives (e.g. "cma-64"?) @xnox - minor correction to your query in comment 8: the fkms overlay is not included on classic. It was never included on there previously, so I couldn't justify breaking boot on the 3A+ just for the sake of bringing the two platforms into line (much as I might desire such harmony for ease of maintenance!). Hence, the only combination where one needed to fiddle with things to get it booting was Core 18 on the 3A+. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1878432 Title: rpi3a+ does not boot with core20 To manage notifications about this bug go to: https://bugs.launchpad.net/pi2-kernel-snap/+bug/1878432/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
