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

[Konrad Dybcio]

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@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.

I'd say all of that hardware should be kept enabled, if only to
make sure that it's parked safely

Konrad