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From: neil.armstrong@linaro.org
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFT 4/7] phy: qcom: qmp-combo: register a typec mux to change the QPHY_MODE
Date: Thu, 29 Feb 2024 16:57:43 +0100	[thread overview]
Message-ID: <a0a082b6-7647-4fd9-b0da-db973ae09f27@linaro.org> (raw)
In-Reply-To: <CAA8EJpq0E_t6bi4TymtpxdX0ZHHNJgBU2gFEEZDWSUZg27pEvw@mail.gmail.com>

On 29/02/2024 16:54, Dmitry Baryshkov wrote:
> On Thu, 29 Feb 2024 at 17:47, Neil Armstrong <neil.armstrong@linaro.org> wrote:
>>
>> On 29/02/2024 16:25, Dmitry Baryshkov wrote:
>>> On Thu, 29 Feb 2024 at 15:08, Neil Armstrong <neil.armstrong@linaro.org> wrote:
>>>>
>>>> Register a typec mux in order to change the PHY mode on the Type-C
>>>> mux events depending on the mode and the svid when in Altmode setup.
>>>>
>>>> The DisplayPort phy should be left enabled if is still powered on
>>>> by the DRM DisplayPort controller, so bail out until the DisplayPort
>>>> PHY is not powered off.
>>>>
>>>> The Type-C Mode/SVID only changes on plug/unplug, and USB SAFE states
>>>> will be set in between of USB-Only, Combo and DisplayPort Only so
>>>> this will leave enough time to the DRM DisplayPort controller to
>>>> turn of the DisplayPort PHY.
>>>
>>> I think this is not fully correct. Please correct me if I'm wrong, but
>>> it is possible to switch between USB / USB+DP / DP-only at runtime.
>>> See the Status Update and Configure commands.
>>
>> Yes, but the current implementation is still valid because we need to
>> have the DP powered-off before changing the PHY mode.
> 
> Even for switching between 2 lane and 4 lane modes?

So the Altmode pin assignment says how much lanes you can get (2 or 4),
and AUX data will say how much the adapter/display supports.

My native DP monitor uses the 4 lanes, while my USB-C->HDMI dongles
declares the 4lanes pin assigment but DP controller only ever tries 2 lanes.

I don't have USB-C->HDMI with 4lanes DP, but it should work fine.

Neil

> 
> I'll check how my USB-A+DP dongles work with respect to the altmode
> configuration.
> 
>>
>> I never encountered such setup and I have no idea how to test this.
>>
>>>
>>>>
>>>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> 
> 


  reply	other threads:[~2024-02-29 15:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-29 13:07 [PATCH RFT 0/7] arm64: qcom: allow up to 4 lanes for the Type-C DisplayPort Altmode Neil Armstrong
2024-02-29 13:07 ` [PATCH RFT 1/7] dt-bindings: phy: qcom,sc8280xp-qmp-usb43dp: Add mode-switch Neil Armstrong
2024-03-04 16:22   ` Rob Herring
2024-02-29 13:07 ` [PATCH RFT 2/7] phy: qcom: qmp-combo: store DP phy power state Neil Armstrong
2024-02-29 13:07 ` [PATCH RFT 3/7] phy: qcom: qmp-combo: introduce QPHY_MODE Neil Armstrong
2024-03-29 16:56   ` Vinod Koul
2024-02-29 13:07 ` [PATCH RFT 4/7] phy: qcom: qmp-combo: register a typec mux to change the QPHY_MODE Neil Armstrong
2024-02-29 15:25   ` Dmitry Baryshkov
2024-02-29 15:47     ` Neil Armstrong
2024-02-29 15:54       ` Dmitry Baryshkov
2024-02-29 15:57         ` neil.armstrong [this message]
2024-02-29 13:07 ` [PATCH RFT 5/7] arm64: dts: qcom-sm8550: allow 4 lanes for DisplayPort and enable QMP PHY mode-switch Neil Armstrong
2024-02-29 13:07 ` [PATCH RFT 6/7] arm64: dts: qcom-sm8650: " Neil Armstrong
2024-02-29 13:07 ` [PATCH RFT 7/7] arm64: dts: qcom-mode-switch: " Neil Armstrong
2024-02-29 13:11   ` Neil Armstrong
2024-03-01  3:00   ` Bjorn Andersson
2024-03-01 18:31     ` Neil Armstrong
2024-03-15 17:19 ` [PATCH RFT 0/7] arm64: qcom: allow up to 4 lanes for the Type-C DisplayPort Altmode Luca Weiss
2024-03-15 17:35   ` Neil Armstrong
2024-03-16 16:01     ` Bjorn Andersson
2024-03-18 10:45       ` Luca Weiss
2024-03-26 21:02       ` Konrad Dybcio
2024-03-29  9:02         ` Luca Weiss
2024-04-05  8:08           ` Neil Armstrong
2024-04-05 10:19             ` Luca Weiss
2024-04-23 13:03               ` Konrad Dybcio
2024-04-23 14:08                 ` neil.armstrong
2024-05-10  6:51                   ` Luca Weiss
2024-05-23  9:06                     ` neil.armstrong
2024-05-24  6:51                       ` Luca Weiss
2024-05-24  7:08                         ` neil.armstrong

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