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

[Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>]

On 23/06/2026 13:38, Konrad Dybcio wrote:
> On 6/23/26 1:31 PM, Krzysztof Kozlowski wrote:
>> 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@oss.qualcomm.com>
>>> ---
>>>  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.
> 
> I'd say all of that hardware should be kept enabled, if only to
> make sure that it's parked safely
> 

You mean enable DSI PHY, even though there is nothing attached?

My warning probably can be fixed same way as:
https://lore.kernel.org/all/20260622-sm8450-qol-v1-1-37e2ee8df9da@proton.me/


Best regards,
Krzysztof