On Wed, 9 Oct 2019 at 16:11, Markus Birth <1847...@bugs.launchpad.net> wrote: > > > I'd *guess* that's a limitation due to u-boot, but I'll try and find > > time to test the kernel alone to confirm that. Obviously it's > > something we'll want to sort out fairly quickly but I suspect it'll > > have to be post-release at this point. > > For me, the Raspberry never leaves the rainbow screen if I omit the > total_mem=1024. So it doesn't seem to be a thing with u-boot (which I > don't use). I've read reports of people that can boot their (custom) > kernels with 3GB RAM but get lockups with 4GB ... so I'll experiment > with that, too. But they might have been using a 32bit kernel.
Confirmed it's a u-boot issue: https://bugs.launchpad.net/ubuntu/+source/u-boot/+bug/1847500 Incidentally, both the tests in that bug were without the total_mem=1024 line (I just adjusted the kernel line and added an initramfs line to our default config.txt when booting the kernel directly). I'd guess the issue in your case is that you've got an older kernel which doesn't support the Pi4 (or your firmware package is out of date which'd mean you don't have start4.elf et al under /boot/firmware). The version of the linux-image-raspi2 package on the eoan daily is 5.3.0.1005.1 so you probably need that or later, and you'll want linux-firmware-raspi2 at 1.20190819-0ubuntu1 or later. > This guy built a custom system image (with custom kernel) based on > bionic that seems to be able to access all 4GB: > > https://jamesachambers.com/raspberry-pi-4-ubuntu-server-desktop-18-04-3 > -image-unofficial/ > > But since I want to use the official kernel, I never tested it. However, > he has the kernel config and boot config on his GitHub (link is on that > page). So maybe this helps. It appears the new Eoan kernel can access all 4Gb (at least, I saw "3884464" Kb free which looks about right for 4Gb with a bit reserved for the GPU). Not sure what magic the kernel team wove to achieve that, but I'll see if we can do something similar for u-boot :) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1847163 Title: [FFe] Firmware bump for Pi 4 boot support To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-firmware-raspi2/+bug/1847163/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
