[PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Mahadevan P]

Add the mode-switch property to the QMP combo PHY so that mode-switch
events are routed to it, allowing the PHY to enter DisplayPort Alternate
Mode. Expand the DP data-lanes assignment from two to four lanes to make
use of the full link bandwidth available in this configuration.

Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
---
 arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
index e393ccf1884a..0c180e49816f 100644
--- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
+++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
@@ -789,7 +789,7 @@ &mdss_dp {
 };
 
 &mdss_dp_out {
-	data-lanes = <0 1>;
+	data-lanes = <0 1 2 3>;
 	remote-endpoint = <&usb_dp_qmpphy_dp_in>;
 };
 
@@ -1391,6 +1391,7 @@ &usb_1_qmpphy {
 	vdda-phy-supply = <&vreg_l6b_1p2>;
 	vdda-pll-supply = <&vreg_l1b_0p912>;
 
+	mode-switch;
 	orientation-switch;
 
 	status = "okay";

---
base-commit: 452c3b1ea875276105ac90ba474f72b4cd9b77a2
change-id: 20260417-kodiak_4k-891ef2221e4b

Best regards,
-- 
Mahadevan P <mahadevan.p@oss.qualcomm.com>

Re: [PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Neil Armstrong]

On 4/20/26 12:00, Mahadevan P wrote:
> Add the mode-switch property to the QMP combo PHY so that mode-switch
> events are routed to it, allowing the PHY to enter DisplayPort Alternate
> Mode. Expand the DP data-lanes assignment from two to four lanes to make
> use of the full link bandwidth available in this configuration.
> 
> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
> ---
>   arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> index e393ccf1884a..0c180e49816f 100644
> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> @@ -789,7 +789,7 @@ &mdss_dp {
>   };
>   
>   &mdss_dp_out {
> -	data-lanes = <0 1>;
> +	data-lanes = <0 1 2 3>;

This property should be moved to kodiak.dtsi

>   	remote-endpoint = <&usb_dp_qmpphy_dp_in>;
>   };
>   
> @@ -1391,6 +1391,7 @@ &usb_1_qmpphy {
>   	vdda-phy-supply = <&vreg_l6b_1p2>;
>   	vdda-pll-supply = <&vreg_l1b_0p912>;
>   
> +	mode-switch;
>   	orientation-switch;

Same for those.

Neil

>   
>   	status = "okay";
> 
> ---
> base-commit: 452c3b1ea875276105ac90ba474f72b4cd9b77a2
> change-id: 20260417-kodiak_4k-891ef2221e4b
> 
> Best regards,

Re: [PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Konrad Dybcio]

On 4/20/26 12:00 PM, Mahadevan P wrote:
> Add the mode-switch property to the QMP combo PHY so that mode-switch
> events are routed to it, allowing the PHY to enter DisplayPort Alternate
> Mode. Expand the DP data-lanes assignment from two to four lanes to make
> use of the full link bandwidth available in this configuration.
> 
> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
> ---
>  arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> index e393ccf1884a..0c180e49816f 100644
> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
> @@ -789,7 +789,7 @@ &mdss_dp {
>  };
>  
>  &mdss_dp_out {
> -	data-lanes = <0 1>;
> +	data-lanes = <0 1 2 3>;
>  	remote-endpoint = <&usb_dp_qmpphy_dp_in>;

There was an issue with this on a similar kodiak-iot board:

https://lore.kernel.org/linux-arm-msm/zjmf27y5i6ypba3nvsxxceuxn6yogp46lmtrjua37qa4ibrleq@4qv5s2wirgdh/

Have you confirmed (through debugfs) that 4 lanes are in use when
running this on r3g2?


>  };
>  
> @@ -1391,6 +1391,7 @@ &usb_1_qmpphy {
>  	vdda-phy-supply = <&vreg_l6b_1p2>;
>  	vdda-pll-supply = <&vreg_l1b_0p912>;
>  
> +	mode-switch;

This should be moved to kodiak.dtsi

Konrad

Re: [PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Mahadevan P]

On 4/22/2026 4:19 PM, Konrad Dybcio wrote:
> On 4/20/26 12:00 PM, Mahadevan P wrote:
>> Add the mode-switch property to the QMP combo PHY so that mode-switch
>> events are routed to it, allowing the PHY to enter DisplayPort Alternate
>> Mode. Expand the DP data-lanes assignment from two to four lanes to make
>> use of the full link bandwidth available in this configuration.
>>
>> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
>> ---
>>   arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> index e393ccf1884a..0c180e49816f 100644
>> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>> @@ -789,7 +789,7 @@ &mdss_dp {
>>   };
>>   
>>   &mdss_dp_out {
>> -	data-lanes = <0 1>;
>> +	data-lanes = <0 1 2 3>;
>>   	remote-endpoint = <&usb_dp_qmpphy_dp_in>;
> 
> There was an issue with this on a similar kodiak-iot board:
> 
> https://lore.kernel.org/linux-arm-msm/zjmf27y5i6ypba3nvsxxceuxn6yogp46lmtrjua37qa4ibrleq@4qv5s2wirgdh/
> 
> Have you confirmed (through debugfs) that 4 lanes are in use when
> running this on r3g2?
> 

yes
root@rb3gen2-core-kit:/sys/kernel/debug/dri/0/DP-1# cat  dp_debug

         name = msm_dp

         drm_dp_link

                 rate = 540000

                 num_lanes = 4

                 capabilities = 1

         dp_panel_info:

                 active = 3840x2160

                 back_porch = 80x54

                 front_porch = 48x3

                 sync_width = 32x5

                 active_low = 0x0

                 h_skew = 0

                 refresh rate = 60

                 pixel clock khz = 533250

                 bpp = 30

         dp_link:

                 test_requested = 128

                 num_lanes = 4

                 bw_code = 20

                 lclk = 540000000

                 v_level = 2

                 p_level = 0


> 
>>   };
>>   
>> @@ -1391,6 +1391,7 @@ &usb_1_qmpphy {
>>   	vdda-phy-supply = <&vreg_l6b_1p2>;
>>   	vdda-pll-supply = <&vreg_l1b_0p912>;
>>   
>> +	mode-switch;
> 
> This should be moved to kodiak.dtsi
sure
> 
> Konrad

Re: [PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Konrad Dybcio]

On 4/22/26 2:31 PM, Mahadevan P wrote:
> 
> 
> On 4/22/2026 4:19 PM, Konrad Dybcio wrote:
>> On 4/20/26 12:00 PM, Mahadevan P wrote:
>>> Add the mode-switch property to the QMP combo PHY so that mode-switch
>>> events are routed to it, allowing the PHY to enter DisplayPort Alternate
>>> Mode. Expand the DP data-lanes assignment from two to four lanes to make
>>> use of the full link bandwidth available in this configuration.
>>>
>>> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
>>> ---
>>>   arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>>> index e393ccf1884a..0c180e49816f 100644
>>> --- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>>> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
>>> @@ -789,7 +789,7 @@ &mdss_dp {
>>>   };
>>>     &mdss_dp_out {
>>> -    data-lanes = <0 1>;
>>> +    data-lanes = <0 1 2 3>;
>>>       remote-endpoint = <&usb_dp_qmpphy_dp_in>;
>>
>> There was an issue with this on a similar kodiak-iot board:
>>
>> https://lore.kernel.org/linux-arm-msm/zjmf27y5i6ypba3nvsxxceuxn6yogp46lmtrjua37qa4ibrleq@4qv5s2wirgdh/
>>
>> Have you confirmed (through debugfs) that 4 lanes are in use when
>> running this on r3g2?
>>
> 
> yes

Thanks for confirming!

Konrad

Re: [PATCH] arm64: dts: qcom: qcs6490-rb3gen2: Enable 4-lane DisplayPort Alt Mode

[Dmitry Baryshkov]

On Mon, Apr 20, 2026 at 03:30:02PM +0530, Mahadevan P wrote:
> Add the mode-switch property to the QMP combo PHY so that mode-switch
> events are routed to it, allowing the PHY to enter DisplayPort Alternate
> Mode. Expand the DP data-lanes assignment from two to four lanes to make
> use of the full link bandwidth available in this configuration.
> 
> Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com>
> ---
>  arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry