[PATCH v2] Revert v6.2-rc1 and later "ARM: dts: bcm2835-rpi: Use firmware clocks for display"

[H. Nikolaus Schaller]

Hi,

> Am 20.01.2025 um 17:34 schrieb Florian Fainelli <florian.fainelli at broadcom.com>:
> 
> 
> 
> On 1/19/2025 7:04 AM, 'H. Nikolaus Schaller' via BCM-KERNEL-FEEDBACK-LIST,PDL wrote:
>> Hi Stefan,
>>> Am 19.01.2025 um 01:36 schrieb Stefan Wahren <wahrenst at gmx.net>:
>>> 
>>> Hi,
>>> 
>>> Am 18.01.25 um 17:27 schrieb H. Nikolaus Schaller:
>>>> This reverts commit 27ab05e1b7e5c5ec9b4f658e1b2464c0908298a6.
>>>> 
>>>> I tried to upgrade a RasPi 3B+ with Waveshare 7inch HDMI LCD
>>>> from 6.1.y to 6.6.y but found that the display is broken with
>>>> this log message:
>>>> 
>>>> [   17.776315] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_drm_unregister [vc4])
>>>> [   17.784034] platform 3f806000.vec: deferred probe pending
>>>> 
>>>> Some tests revealed that while 6.1.y works, 6.2-rc1 is already broken but all
>>>> newer kernels as well. And a bisect did lead me to this patch.
>>> I successfully tested every Kernel release until Linux 6.13-rc with the
>>> Raspberry Pi 3B+, so i prefer to step back and analyze this issue further.
>> Yes, I would be happy with any solution.
>>> What kernel config do you use ?
>> a private one which enables application specific drivers.
>>> What is the value of CONFIG_CLK_RASPBERRYPI ?
>> CONFIG_CLK_RASPBERRYPI is not set
>> I checked where this is defined and it is in bcm2835_defconfig and
>> multi_v7_defconfig by
>> 4c6f5d4038af2c ("ARM: defconfig: enable cpufreq driver for RPi")
>> which hides this requirement quite well and got therefore unnoticed...
>> Setting CONFIG_CLK_RASPBERRYPI=y makes HDMI work without my proposed revert.
>> Tested with v6.2.16, v6.6.72, v6.12.10 and v6.13-rc7.
> 
> I have been burned before by something similar and came up with this patch series that I should resubmit after addressing Conor's comment:
> 
> https://lore.kernel.org/all/20240513235234.1474619-1-florian.fainelli@broadcom.com/
> 
> Essentially, it removes the guess work, all you have to do is enable CONFIG_ARCH_BCM2835 and it just works, which is how it should be IMHO.

Sounds like a good idea!

Supported-by: H. Nikolaus Schaller <hns at goldelico.com>

BR,
Nikoalus