[PATCH] ARM: dts: imx6qdl-udoo: Disable USB host to work around boot issues

[Fabio Estevam]

On Sun, May 1, 2022 at 7:35 PM Fabio Estevam <festevam at gmail.com> wrote:
>
> [Adding Baruch and Josua]
>
> On Sun, May 1, 2022 at 2:47 PM Mark Brown <broonie at kernel.org> wrote:
> >
> > Attempting to boot my Udoo Dual and Quad with mainline hangs during boot
> > after printing:
> >
> > [    3.270471] imx_usb 2184000.usb: No over current polarity defined
> > [    3.922502] mxs_phy 20c9000.usbphy: Data pin can't make good contact.
> > [    3.940097] imx_usb 2184200.usb: No over current polarity defined
> >
> > where imx_usb 2184200.usb is usbh1 in the DT. Adding debug prints to the
> > code seems to show that we lock up at the first read in usbmisc_imx6q_init()
> > which in combination with the above logging about the USB controllers
> > suggests that we lock up on the first read in usbmisc_imx6q_init(). Looking
> > at some of the other i.MX6 boards and the warning messages that are being
> > printed suggests that there is bitrot in the DTS for the device so disable
> > it for now, with it disabled the board boots successfully.  Clearly this is
> > not a real fix, but it does allow some use of the board with mainline.
> >
> > Similar behaviour is seen all the way back as far as v4.19, I tried going
> > back to when the board was added but had toolchain issues. Vendor provided
> > binaries seem fine on the boards so it seems likely that the hardware is
> > fine and the issue is with some combination of the DT and kernel.  This
> > should obviously be resolved properly but for now this at least allows
> > the kernel to boot with reduced functionality on these systems.
>
> My imx6-cubox is no longer functional, so I cannot verify this myself.
>
> Baruch and Josua,
>
> Are you aware of this issue?

Oops, sorry for the confusion. It's an udoo board, not a cubox.

Mark, I recall I sent this some time ago:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/1516278858-15464-1-git-send-email-fabio.estevam@nxp.com/

And I still carry this patch in Buildroot to avoid the kernel hang:
https://github.com/buildroot/buildroot/blob/master/board/udoo/mx6qdl/patches/linux/0000-udoo-disable-usbh1.patch

I still think we need it:

Reviewed-by: Fabio Estevam <festevam at gmail.com>