Re: [PATCH] arm64: dts: qcom: eliza: Fix disp_cc_mdss_mdp_clk_src RCG stall on Eliza EVK

[Krzysztof Kozlowski]

On 23/06/2026 13:27, Krzysztof Kozlowski wrote:
> Eliza EVK (eliza-cqs-evk.dts) does not have display enabled, however its
> Display Clock Controller is enabled and references parent clocks from
> DSI PHYs.  Devices which in base DTSI do not have all required resources
> available (e.g. because they are simply disabled), should not be enabled
> in the first place.
> 
> Having DISPCC enabled without DSI PHYs causes clock reparenting issues
> and warning on Eliza EVK:
> 
>   disp_cc_mdss_mdp_clk_src: rcg didn't update its configuration.
>   WARNING: drivers/clk/qcom/clk-rcg2.c:136 at update_config+0xd4/0xe4, CPU#1: udevd/273
>   ...
>     update_config (drivers/clk/qcom/clk-rcg2.c:136 (discriminator 2)) (P)
>     clk_rcg2_shared_disable (drivers/clk/qcom/clk-rcg2.c:1471)
>     clk_rcg2_shared_init (drivers/clk/qcom/clk-rcg2.c:1540)
>     __clk_register (drivers/clk/clk.c:3959 drivers/clk/clk.c:4368)
>     devm_clk_hw_register (drivers/clk/clk.c:4448 (discriminator 1) drivers/clk/clk.c:4672 (discriminator 1))
>     devm_clk_register_regmap (drivers/clk/qcom/clk-regmap.c:104)
>     qcom_cc_really_probe (drivers/clk/qcom/common.c:418)
>     qcom_cc_probe (drivers/clk/qcom/common.c:445)
>     disp_cc_eliza_probe (dispcc-eliza.c:?) dispcc_eliza
>     platform_probe (drivers/base/platform.c:1432)
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/qcom/eliza-mtp.dts | 4 ++++
>  arch/arm64/boot/dts/qcom/eliza.dtsi    | 1 +
>  2 files changed, 5 insertions(+)


I should call it RFC, because this feels like a band-aid and should be
fixed in clock drivers maybe. Eventually DISPCC should be enabled on
Eliza EVK for HDMI, but DSI PHY will stay disabled.

Best regards,
Krzysztof