drm/vc4: module dysfunctional on Raspberry Pi 3B as of 5.18.0

[Peter Robinson]

On Thu, Jun 9, 2022 at 10:33 PM Stefan Wahren <stefan.wahren at i2se.com> wrote:
>
> Hi Peter,
>
> Am 09.06.22 um 13:52 schrieb Peter Robinson:
> >>>>> As of Linux 5.18.0, module vc4 apparently isn't working on Raspberry Pi
> >>>>> 3B any more.
> >>>>>
> >>>>> If a monitor is attached to the device, the boot messages show up as
> >>>>> usual, but right when KMS starts, the screen turns black. Similarly, the
> >>>>> screen also turns black when the module is blacklisted at boot time and
> >>>>> loaded from the running system.
> >>>>> The problem looks quite similar to the one posted some months ago in [1].
> >>> If I understand you properly, it results in a blank screen if the
> >>> monitor is connected, but the system is still responsive?
> >>>
> >>> If so, it's a very different problem than the link you provided, since
> >>> it was occurring when no monitor was connected and resulted in a total
> >>> system hang.
> >>>
> >>>>> Unfortunately, looking through systemd's journal didn't seem to yield
> >>>>> any real hint. Nevertheless, the results from grepping vc4 are
> >>>> I'm seeing the same issue with vc4 on a RPi3 on 5.18.1 on Fedora so
> >>>> can confirm the regression. Maxime would know what might be up here?
> >> i assume you are using the downstream DTB?
> > In this case it's the one in the Linux kernel (not sure if that's
> > upstream or downstream in this context) not the one provided by the
> > RPi firmware.
>
> okay thanks. I tried the kernel config but its huge.

Welcome to distro configs.

> Is it correct that the issue occurs with your kernel config, but not
> with multi_v7_defconfig?

I've not tried it, ultimately the distro config is where it's used and
the rpi config within that hasn't changed for some time.

> >
> >> Please provide the version/date of the GPU firmware?
> > [    6.205121] raspberrypi-firmware soc:firmware: Attached to firmware
> > from 2022-05-24T13:26:52
> > Which is git f145afc
> This is good. I had issues with older firmware which didn't implement
> RPI_FIRMWARE_NOTIFY_DISPLAY_DONE. So it must be something different.