Re: BUG - was: [GIT PULL 2/3] bcm2835-soc-next-2019-10-15

[H. Nikolaus Schaller]

Hi all,
I think I have found the issue, it is not ZONE_DMA, see below.

> Am 14.12.2019 um 17:54 schrieb Stefan Wahren <wahrenst@xxxxxxx>:
> 
> Hi Nikolaus,
> 
> [add Nicolas as the new BCM2835 maintainer]
> 
> Am 14.12.19 um 11:54 schrieb H. Nikolaus Schaller:
>> Hi Stefan,
>> 
>>> Am 15.10.2019 um 19:15 schrieb Stefan Wahren <wahrenst@xxxxxxx>:
>>> 
>>> Hi Florian,
>>> 
>>> The following changes since commit 54ecb8f7028c5eb3d740bb82b0f1d90f2df63c5c:
>>> 
>>> Linux 5.4-rc1 (2019-09-30 10:35:40 -0700)
>>> 
>>> are available in the git repository at:
>>> 
>>> git://github.com/anholt/linux tags/bcm2835-soc-next-2019-10-15
>>> 
>>> for you to fetch changes up to 781fa0a954240c8487683ddf837fb2c4ede8e7ca:
>>> 
>>> ARM: bcm: Add support for BCM2711 SoC (2019-10-10 19:21:03 +0200)
>> this patch has finally arrived in v5.5-rc1 but it seems to break
>> multiplatform build.
>> 
>> We run a distribution kernel that supports OMAP3/4/5, i.MX6 and RasPi 3B+
>> but since rebasing to v5.5-rc1 the kernel hangs after "Starting Kernel ...".
>> On all ARM devices (incl. RasPi 3B+).
> 
> i wasn't able to reproduce this issue with the RPi 3B+ so far and i
> don't have any OMAP hardware:
> 
> Linux 5.3 (bcm2835_defconfig) + FW 2019-02-12 => okay
> Linux 5.3 (bcm2835_defconfig + ZONE_DMA) + FW 2019-02-12 => okay
> Linux 5.5-rc1 (bcm2835_defconfig) + FW 2019-02-12 => okay
> Linux 5.5-rc1 (multi_v7_defconfig) + FW 2019-02-12 => okay
> 
> So please provide more information about your RPi 3B+ setup:
> 
> - VC firmware version
> - additional bootloader (U-Boot)
> - boot source (SD card, USB, network)
> - kernel config
> 
> Did you tested the mainline kernel or the letux kernel?

On the OMAP I did test the mainline kernel with omap2plus_defconfig.
RasPi 3B+ experiment was with Letux kernel and config.


But I was lucky to find the issue by code inspection:

bcm2711_compat[] is missing a NULL sentinel.

Therefore, enabling CONFIG_ARCH_BCM2835 is sufficient to trigger the
problem unless you may have been lucky getting something starting with
a NULL packed after it on your bcm2835_defconfig or multi_v7_defconfig
build.

Patch submitted.

BR,
Nikolaus