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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Fri, 29 Oct 2021 18:16:14 -0500
Message-ID: <CAE-0n50JTi+62Nzs+Lc4h4PGDdzEV2Ojm+OD+sqM1LDqC_QSow@mail.gmail.com>
Subject: Re: [PATCH v3 2/4] arm64: dts: sc7180: Specify "data-lanes" for DSI
 host output
To:     LKML <linux-kernel@vger.kernel.org>,
        Philip Chen <philipchen@chromium.org>
Cc:     dianders@chromium.org, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-arm-msm@vger.kernel.org
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Quoting Philip Chen (2021-10-29 15:27:41)
> MSM DSI host driver actually parses "data-lanes" in DT and compare
> it with the number of DSI lanes the bridge driver sets for
> mipi_dsi_device. So we need to always specify "data-lanes" for the
> DSI host output. As of now, "data-lanes" is added to ti-sn65dsi86 dts
> fragment, but missing in parade-ps8640 dts fragment, which requires
> a fixup.

I don't see data-lanes required in the schema, and
dsi_host_parse_lane_data() seems happy to continue without it. I do see
that num_data_lanes isn't set though. Does this patch fix it?

----8<----
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c
b/drivers/gpu/drm/msm/dsi/dsi_host.c
index e269df285136..f6fba07220e5 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1696,6 +1696,7 @@ static int dsi_host_parse_lane_data(struct
msm_dsi_host *msm_host,
 	if (!prop) {
 		DRM_DEV_DEBUG(dev,
 			"failed to find data lane mapping, using default\n");
+		msm_host->num_data_lanes = 4;
 		return 0;
 	}