Saturday, March 5, 2022

[fedora-arm] Re: Change in kernel PPS GPIO handling?

Am 04.03.22 um 21:50 schrieb Stefan Wahren:
> Am 03.03.22 um 02:29 schrieb Chris Adams:
>> Once upon a time, Stefan Wahren <> said:
>>> Hi Chris,
>>> Am 02.03.22 um 10:51 schrieb Peter Robinson:
>>>>> I have an RPi4 running Fedora 35. It hadn't been updated in a while, so
>>>>> I applied updates today. When I boot to the kernel 5.16.11-200, I lose
>>>>> the PPS device from my GPS hat. Boot back to 5.14.16-301.fc35 and it
>>>>> works.
>>>>> I'm booting with EFI firmware, and with a device tree config.txt that
>>>> All our firmware are EFI, that's the only way we support booting, is
>>>> it the default U-Boot based one or are you using the edk2 one?
>>>>> has "dtoverlay=pps-gpio,gpiopin=4" in it. I removed the /boot/dtb
>>>>> symlink and set /etc/u-boot.conf to not re-add it.
>>>>> When I boot 5.16, I see /proc/device-tree, and it has
>>>>> /proc/device-tree/pps@4 in it (and the contents look correct), but
>>>>> loading the pps-gpio kernel module just gives:
>>>>> pps-gpio: probe of pps@4 failed with error -22
>>>> Any chance you can tell us which kernel it started with, 5.14.x to
>>>> 5.16.x is a big window to debug and looking at kernel logs for
>>>> drivers/pps there's been no changes in that space in the 5.15+ kernels
>>>> at all.
>>>> I wonder if it's a change/regression in the firmware overlay <->
>>>> kernel interface.
>>> do you use the DTB file from 5.14.x or 5.16x?
>>> I guess this is related to this commit:
>>> Unfortunately this is a change which requires this DTS fix:
>>> So DTB and kernel must "match".
>> Okay, so what's the best way to do that?
>> I have EFI firmware from in /boot/efi, and
>> the /boot/dtb symlink removed. The bcm2711-rpi-4-b.dtb file in
>> /boot/efi is from the file. I have a
>> config.txt in /boot/efi that references overlays in /boot/efi/overlays
>> from RPM bcm283x-overlays (like pps-gpio)..
>> I'm not quite sure how I need to fit all this together.
> Let me recap the situation. mainline and rpi vendor tree are independent
> in development. Synchronization (incl. device tree) happens in both
> directions.
> U-Boot bootloader decided to keep an own copy of the mainline DT files
> (which is currently based on an older 5.15 version which lacks the
> gpio-ranges property). According to this statement [1] the EDK2 UEFI
> decided to use the rpi vendor tree and don't care about the mainline DT
> files.
> I'm sorry but as a spare-time kernel developer, i don't have to time to
> fight against all this mess.
> I hope i will have some time for debugging in the near future ...
> [1] -
Today i tried Fedora 35 Minimal for my first time, here are my test results:

Raspberry Pi 400 32 bit => bus width issue
Raspberry Pi 400 64 bit => hangs while show graphics
Raspberry Pi 4 B 4 GB 32 bit => kernel crash
Raspberry Pi 4 B 4 GB 64 bit => boot into setup
Raspberry Pi 4 B 8 GB 32 bit => black screen, fails to start kernel?
Raspberry Pi 4 B 8 GB 64 bit => boot into setup

At least the 32 bit issues on Raspberry Pi 4 are expected since the
kernel config doesn't have ARM_LPAE enabled.

arm mailing list --
To unsubscribe send an email to
Fedora Code of Conduct:
List Guidelines:
List Archives:
Do not reply to spam on the list, report it:

No comments:

Post a Comment