Re: [PATCH] clk: qcom: dispcc-sc8280xp: Don't park mdp_clk_src at registration time

Re: [PATCH] clk: qcom: dispcc-sc8280xp: Don't park mdp_clk_src at registration time

[Jérôme de Bretagne]

> Parking disp{0,1}_cc_mdss_mdp_clk_src clk broke simplefb on HUAWEI
> Gaokun3, the image will stuck at grey for seconds until msm takes
> over framebuffer. Use clk_rcg2_shared_no_init_park_ops to skip it.
>
> Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>

This patch allows to keep the built-in display enabled on the Microsoft
Surface Pro 9 5G (Arcata) using efifb and software rendering. This was
achieved by passing the "module_blacklist=msm" option. It is really
useful as the built-in display is not yet working thus not described
in the arcata devicetree so far.

Thank you Pengyu.

Tested-by: Jérôme de Bretagne <jerome.debretagne@gmail.com>


Without this patch, the initial EFI framebuffer gets disabled a few
seconds after the initial boot messages. This has been a regression
as it used to work when doing the initial bringup with Linux 6.9.

As mentioned in the similar patchset for the x1e80100 dispcc driver
https://lore.kernel.org/all/67a51928-1c16-48a6-ac65-f67c36297e5e@oss.qualcomm.com/
according to Hans, this should be a fix for the following commit:

Fixes: 01a0a6cc8cfd ("clk: qcom: Park shared RCGs upon registration")


Regards,
Jérôme