Commit 8ae030c34 breaks USB on the Raspberry Pi 4

[Florian Fainelli]

+Nicolas, Stefan,

On 9/14/21 2:28 PM, Michael Stapelberg wrote:
> [re-sending in plain text mode]
> 
> Hey!
> 
> Linux 5.14 broke USB on the Raspberry Pi 4 for me.
> 
> See https://github.com/gokrazy/kernel/commit/e06b78841ba4d2ce99a3f368cb8407951267e082
> for more details regarding symptoms and a dmesg diff.
> 
> I used git-bisect to find the culprit, and it identified this commit:
> https://github.com/torvalds/linux/commit/8ae030c34dce4f5764e945b325e8dc4d2adef044
> 
> Indeed, when I compare the kernel config before/with the commit, I see:
> 
> --- /tmp/config-WORKING 2021-09-14 23:04:03.180316634 +0200
> +++ /tmp/config-BROKEN 2021-09-14 23:05:57.475549129 +0200
> @@ -8101,7 +8101,7 @@
>  CONFIG_RESET_MESON_AUDIO_ARB=m
>  CONFIG_RESET_QCOM_AOSS=y
>  CONFIG_RESET_QCOM_PDC=m
> -CONFIG_RESET_RASPBERRYPI=y
> +CONFIG_RESET_RASPBERRYPI=m
>  CONFIG_RESET_SCMI=y
>  CONFIG_RESET_SIMPLE=y
>  CONFIG_RESET_SUNXI=y
> 
> So it seems like this innocuous-looking arm64 defconfig change has
> accidentally (?) demoted CONFIG_RESET_RASPBERRYPI=y to
> CONFIG_RESET_RASPBERRYPI=m in the arm64 defconfig.
> 
> Was this intentional? If not, I’d be happy if you could send a fix for
> this change.

>From a running system, can you see if reset-raspberry.ko is included in
your root filesystem? If not, this would definitively be an issue since
that driver is needed in order for xHCI to work on the Pi 4. There does
not appear to be any explicit dependency between reset-raspberry and
xhci-pci.ko, so without manually "front" loading the former before the
latter, I don't think we can have automatic dependencies.

> 
> Thank you!
> Best regards
> Michael
> 
> PS: I’m building the Linux kernel using this config addition to the
> arm64 defconfig:
> https://github.com/gokrazy/kernel/blob/master/cmd/gokr-build-kernel/build.go#L19,
> just in case it matters…
> 
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> 


-- 
Florian