Re: [PATCH 2/4] drm/msm/dp: clear force_link_train flag when link training succeeds

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Saurabh Anand <saurabh.anand@oss.qualcomm.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Manivannan Sadhasivam <mani@kernel.org>,
	Rob Clark <robin.clark@oss.qualcomm.com>,
	Dmitry Baryshkov <lumag@kernel.org>,
	Abhinav Kumar <abhinav.kumar@linux.dev>,
	Jessica Zhang <jesszhan0024@gmail.com>,
	Sean Paul <sean@poorly.run>,
	Marijn Suijten <marijn.suijten@somainline.org>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>
Cc: linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org,
	Ritesh Kumar <quic_riteshk@quicinc.com>,
	Vishnuvardhan Prodduturi <quic_vproddut@quicinc.com>,
	Mani Chandana Kuntumalla <quic_mkuntuma@quicinc.com>,
	Mahadevan P <mahadevan.p@oss.qualcomm.com>
Subject: Re: [PATCH 2/4] drm/msm/dp: clear force_link_train flag when link training succeeds
Date: Mon, 24 Aug 2026 15:17:20 +0200	[thread overview]
Message-ID: <2b1e73f4-a476-4dc8-83f2-42be1008c1fc@oss.qualcomm.com> (raw)
In-Reply-To: <20260824-qcom-dp-typec-reconnect-fixes-v1-2-2825e5bf8a96@oss.qualcomm.com>

On 8/24/26 1:28 PM, Saurabh Anand wrote:
> msm_dp_display_prepare_link() sets force_link_train = true before calling
> msm_dp_ctrl_on_link(). On success the flag was never cleared, so
> msm_dp_ctrl_prepare_stream_on() would unconditionally trigger a second
> link retrain even though the link was already trained.
> 
> Clear force_link_train on the success path so that
> msm_dp_ctrl_prepare_stream_on() only retrains when the channel EQ check
> fails, as intended.
> 
> Signed-off-by: Saurabh Anand <saurabh.anand@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index bc646d172abe..40e19d506a45 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -649,6 +649,8 @@ static int msm_dp_display_prepare_link(struct msm_dp_display_private *dp)
>  		return rc;
>  	}
>  
> +	force_link_train = false;
> +
>  	return msm_dp_ctrl_prepare_stream_on(dp->ctrl, dp->panel, force_link_train);

This makes the argument of this function useless

Konrad

-- 
linux-phy mailing list
linux-phy@lists.infradead.org
https://lists.infradead.org/mailman/listinfo/linux-phy