Hi Dave, On 16/12/2020 15:23, Dave Jones wrote: > Hi, > > We've recently run across some failures with U-Boot on a couple of platforms, > specifically the relatively new Pi Compute Module 4, and the Pi 4 8GB of RAM. > On > the CM4, U-Boot failed to identify the eMMC storage, and on the Pi 4 8GB, a > crash and reset occurred when U-Boot tried to read from the boot file-system > on > the SD card, but only when booted with no monitor attached (attaching a > monitor > results in a successful boot, at least under arm64). These were with > more-or-less stock rpi_4_defconfig and rpi_4_32b_defconfig configurations from > v2020.10 (our local config changes bump the env-size, enable OF_BOARD, and > RAW_INITRD, but that's it). > > I've bisected the source and figured out roughly the commits responsible; for > the CM4 eMMC case it's the enabling of DMA for the SDHCI interface in > c6b9fbf756. > > The Pi 4 8GB failure was a little more complex in that the bisection pointed > to > 3113c84ba2 (a merge), however that gave me a few clues to try and after a > little > experimenting I found that disabling CONFIG_PCI_BRCMSTB (effectively disabling > the PCI driver for the platform) got things working happily again. > > I'm happy to submit the local patches I'm adding to the Ubuntu build to work > around these, but obviously those fixes are "brute force and ignorance" > patches > that just disable the relevant config; would such patches be wanted, or would > the community prefer to figure out the root causes in each case? I'm happy to > test any patches on the relevant hardware if anyone doesn't have access to the > necessary boards. >
Thanks for looking into this. I'm aware of problems booting CM4 and RPi 400 with PCI. I wasn't aware that RPi4 8GB problem was related to PCI as well. Would you mind to test this series, if this fixes your problems: https://patchwork.ozlabs.org/user/todo/uboot/?series=220661 Regards, Matthias
