[PATCH] arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES)

[Marek Szyprowski]

Hi

On 02.06.2021 15:51, Mark Rutland wrote:
> Hi Marek,
>
> On Wed, Jun 02, 2021 at 03:25:41PM +0200, Marek Szyprowski wrote:
>> On 27.05.2021 14:43, Will Deacon wrote:
>> This patch landed in todays linux-next as commit 65688d2a05de ("arm64:
>> cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES)"). It causes an
>> issue on Raspberry Pi 3b board. System boots to userspace fine, but then
>> it hangs somewhere during the init scripts after loading the modules. I
>> didn't manage to track where it hangs yet though.
> Ouch!
>
> I have a 3b in a drawer that I might be able to reproduce the issue
> with; can you tell me how you're booting that kernel? e.g. which FW and
> DT you're using?

I'm booting the kernel with the mainline dtb 
(arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dtb) from the u-boot, 
which downloads it via TFTP. I don't remember which firmware version is 
there, but without raspberry specific tools (which I don't have deployed 
there) it is hard to check that now. The rootfs is on SD card, the 
system is some older Debian release. Here is the last part of the boot 
log if it helps:

[    7.906329] Freeing unused kernel memory: 8512K
[    7.911793] Run /sbin/init as init process
INIT: version 2.88 booting
[info] Using makefile-style concurrent boot in runlevel S.
ERROR: could not open /proc/stat: No such file or directory
[....] Starting the hotplug events dispatcher: systemd-udevdstarting 
version 236
. ok
[....] Synthesizing the initial hotplug events...[   13.641287] 
bcm2835-rng 3f104000.rng: hwrng registered
[   13.896575] i2c-bcm2835 3f805000.i2c: Could not read clock-frequency 
property
done.
[   13.938691] debugfs: Directory '3f902000.hdmi' with parent 'vc4-hdmi' 
already present!
[   13.983716] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops)
[   13.991816] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops)
[   14.000945] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops)
[   14.009644] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops)
[   14.017547] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops)
[   14.025780] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops)
[   14.033995] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops)
[   14.042196] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops)
[....] Waiting for /dev to be fully populated...[   14.112812] [drm] 
Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
done.
[ ok ] Activating swap...done.
[....] Checking file systems...fsck from util-linux 2.29.2
done.
[ ok ] Cleaning up temporary files... /tmp.
[ ok ] Mounting local filesystems...done.
[ ok ] Activating swapfile swap...done.
[ ok ] Cleaning up temporary files....
[ ok ] Setting kernel variables...done.
[ ok ] Configuring network interfaces...done.
[ ok ] Starting RPC port mapper daemon: rpcbind.
[ ok ] Cleaning up temporary files....
[ ok ] Setting up ALSA...done.
[ ok ] Setting up X socket directories... /tmp/.X11-unix /tmp/.ICE-unix.

Best regards

-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland