Commit 8ae030c34 breaks USB on the Raspberry Pi 4

[Michael Stapelberg]

Thanks for your mail.

My system does not use any Linux kernel modules (=m), all required
code is compiled into the kernel itself (=y).
The root file system does not contain any .ko files.


On Tue, 14 Sept 2021 at 23:47, Florian Fainelli <f.fainelli at gmail.com> wrote:
>
> +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…
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
>
>
> --
> Florian