I poked at this some more tonight, starting with a fresh SD card install of F35. This is in a Pi 4B Rev 1.4 with 4G RAM, and starting with the initial F35 kernel, 5.14.10-300.fc35.aarch64. I can boot that kernel from a card in the on-board SD slot, but then it gets stuck trying to read from that card, with looping errors like: mmc0: error -22 whilst initialising SD card mmc0: invalid bus width So I moved the card to a USB adapter. This is a problem for me, because then I can't set the uboot environment variable to disable stdin from the serial port (so my GPS HAT input on the serial port stops boot); that's why I was using the EDK2 EFI firmware, but for these tests, I stuck with the Fedora-provided uboot firmware and just typed "boot" every time. When I remove the /boot/dtb symlink and edit /boot/efi/config.txt to comment out the "dtoverlay=upstream-pi4" lien and add the following: dtoverlay=disable-bt dtoverlay=disable-wifi dtoverlay=pps-gpio,gpiopin=4 I get my PPS and ttyACM0 devices. Yay, desired outcome. Next, I updated the kernel (to 5.16.11-200.fc35) and uboot-images-armv8 and ran rpi-uboot-update. After reboot, I don't get /dev/pps0, and there's the error: pps-gpio: probe of pps@4 failed with error -22 So, from earlier responses, it seems there's some issue with the different device trees, included with the kernel vs. not? If I use the kernel-included device tree (I guess by not removing /boot/dtb), how do I get the overlays so I can use my GPS hat? Interesting, when I boot 5.16.11-200.fc35 with the /boot/dtb symlink, I lose HDMI signal a little after the kernel loads (I've removed "rhgb quiet" from the boot arg). I can see some kernel messages, but then I lose HDMI. SSHing in, I see in dmesg: [drm] Initialized vc4 0.0.0 20140616 for gpu on minor 0 Unable to handle kernel read from unreadable memory at virtual address 0000000000000348 and so on with a kernel Oops dump. So it seems the kernel-included device tree has its own problems on a Pi 4. -- Chris Adams <linux@xxxxxxxxxxx> _______________________________________________ arm mailing list -- arm@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to arm-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/arm@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
