[PATCH] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers

[PATCH] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers

[Bjorn Andersson]

While MDSS_GDSC is a subdomain of MMCX, Linux does not respect this
relationship and sometimes invokes sync_state on the rpmhpd (MMCX)
before the DisplayPort controller has had a chance to probe.

The result when this happens is that the power is lost to the multimedia
subsystem between the probe of msm_drv and the DisplayPort controller -
which results in an irrecoverable state.

While this is an implementation problem, this aligns the power domain
setting of the one DP instance with that of all the others.

Fixes: 57d6ef683a15 ("arm64: dts: qcom: sc8280xp: Define some of the display blocks")
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
index 4f4353f84cba..4511fd939c91 100644
--- a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
@@ -2533,7 +2533,7 @@ mdss0_dp3: displayport-controller@aea0000 {
 				interrupts = <15>;
 				phys = <&mdss0_dp3_phy>;
 				phy-names = "dp";
-				power-domains = <&dispcc0 MDSS_GDSC>;
+				power-domains = <&rpmhpd SC8280XP_MMCX>;
 
 				assigned-clocks = <&dispcc0 DISP_CC_MDSS_DPTX3_LINK_CLK_SRC>,
 						  <&dispcc0 DISP_CC_MDSS_DPTX3_PIXEL0_CLK_SRC>;
-- 
2.37.3

Re: [PATCH] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers

[Konrad Dybcio]

On 12.01.2023 14:50, Bjorn Andersson wrote:
> While MDSS_GDSC is a subdomain of MMCX, Linux does not respect this
> relationship and sometimes invokes sync_state on the rpmhpd (MMCX)
> before the DisplayPort controller has had a chance to probe.
> 
> The result when this happens is that the power is lost to the multimedia
> subsystem between the probe of msm_drv and the DisplayPort controller -
> which results in an irrecoverable state.
> 
> While this is an implementation problem, this aligns the power domain
> setting of the one DP instance with that of all the others.
> 
> Fixes: 57d6ef683a15 ("arm64: dts: qcom: sc8280xp: Define some of the display blocks")
> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> ---
One day we'll hopefully finally overcome this parent-child mess..

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
>  arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> index 4f4353f84cba..4511fd939c91 100644
> --- a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> @@ -2533,7 +2533,7 @@ mdss0_dp3: displayport-controller@aea0000 {
>  				interrupts = <15>;
>  				phys = <&mdss0_dp3_phy>;
>  				phy-names = "dp";
> -				power-domains = <&dispcc0 MDSS_GDSC>;
> +				power-domains = <&rpmhpd SC8280XP_MMCX>;
>  
>  				assigned-clocks = <&dispcc0 DISP_CC_MDSS_DPTX3_LINK_CLK_SRC>,
>  						  <&dispcc0 DISP_CC_MDSS_DPTX3_PIXEL0_CLK_SRC>;

Re: [PATCH] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers

[Johan Hovold]

On Thu, Jan 12, 2023 at 05:50:55AM -0800, Bjorn Andersson wrote:
> While MDSS_GDSC is a subdomain of MMCX, Linux does not respect this
> relationship and sometimes invokes sync_state on the rpmhpd (MMCX)
> before the DisplayPort controller has had a chance to probe.
> 
> The result when this happens is that the power is lost to the multimedia
> subsystem between the probe of msm_drv and the DisplayPort controller -
> which results in an irrecoverable state.
> 
> While this is an implementation problem, this aligns the power domain
> setting of the one DP instance with that of all the others.
> 
> Fixes: 57d6ef683a15 ("arm64: dts: qcom: sc8280xp: Define some of the display blocks")
> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> ---
>  arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> index 4f4353f84cba..4511fd939c91 100644
> --- a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
> @@ -2533,7 +2533,7 @@ mdss0_dp3: displayport-controller@aea0000 {
>  				interrupts = <15>;
>  				phys = <&mdss0_dp3_phy>;
>  				phy-names = "dp";
> -				power-domains = <&dispcc0 MDSS_GDSC>;
> +				power-domains = <&rpmhpd SC8280XP_MMCX>;
>  
>  				assigned-clocks = <&dispcc0 DISP_CC_MDSS_DPTX3_LINK_CLK_SRC>,
>  						  <&dispcc0 DISP_CC_MDSS_DPTX3_PIXEL0_CLK_SRC>;

Looks good as a temporary remedy:

Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Johan

Re: [PATCH] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers

[Bjorn Andersson]

On Thu, 12 Jan 2023 05:50:55 -0800, Bjorn Andersson wrote:
> While MDSS_GDSC is a subdomain of MMCX, Linux does not respect this
> relationship and sometimes invokes sync_state on the rpmhpd (MMCX)
> before the DisplayPort controller has had a chance to probe.
> 
> The result when this happens is that the power is lost to the multimedia
> subsystem between the probe of msm_drv and the DisplayPort controller -
> which results in an irrecoverable state.
> 
> [...]

Applied, thanks!

[1/1] arm64: dts: qcom: sc8280xp: Use MMCX for all DP controllers
      commit: bb45bb9705372d9335ccd7e3fc5436770ec6d846

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>