Re: [PATCH v2] platform/raspberrypi: vchiq: register bus at subsys_initcall

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Oct 22, 2026 at 10:29:24AM +0200, Martin Wetterwald wrote:
> Since 6.19-rc1, with CONFIG_BCM2835_VCHIQ=y and CONFIG_SND_BCM2835=y
> (both builtin), the sound cards bcm2835_headphones and bcm2835_hdmi are
> not detected anymore (vc4-hdmi is not affected).
> 
> dmesg shows:
> 
>   Driver 'bcm2835-audio' was unable to register with bus_type
>   'vchiq-bus' because the bus was not initialized.
> 
> Since the VCHIQ interface was moved out of staging, its bus is no longer
> guaranteed to be registered before its client drivers. bcm2835-audio,
> still in drivers/staging, registers at device_initcall level and now
> runs first.
> 
> Register the bus and the platform driver at subsys_initcall so the bus
> exists before any client driver, independently of link order. The
> platform driver probe already returns -EPROBE_DEFER while the firmware
> is not ready, so probing earlier is safe. When built as modules, this is
> equivalent to module_init() and nothing changes.
> 
> Tested on Raspberry Pi 1B rev2, 1B+, 2B, 3B and 4B with VCHIQ and
> bcm2835-audio both builtin and both as modules.
> 
> Cc: stable@vger.kernel.org
> Fixes: aa125180c673 ("platform/raspberrypi: Destage VCHIQ interface")
> Reported-by: Martin Wetterwald <martin@wetterwald.eu>
> Closes: https://lore.kernel.org/r/CAFERDQ0FpdVvA5VJxOyRAE_pgxnPVmFx1tkZio5R272j6Bs4tg@mail.gmail.com/
> Reviewed-by: Jai Luthra <jai.luthra@ideasonboard.com>
> Tested-by: Gaston Gonzalez <gascoar@gmail.com> # Raspberry Pi Zero
> Signed-off-by: Martin Wetterwald <martin@wetterwald.eu>
> ---
> Hi Greg,
> this is a regression introduced by aa125180c673 (via your tree) in
> 6.19-rc1 and present in 6.19.y through 7.3.y. If the staging pull for
> 7.4-rc1 has not been sent yet, could you take it there? Otherwise,
> staging-linus would be great. Thanks!

This is not a staging driver anymore, please route it through the proper
tree after -rc1 is out.

thanks,

greg k-h