Re: [PATCH v4 13/39] drm/msm/dp: introduce stream_id for each DP panel

Dmitry Baryshkov
2026-04-11T18:04:25Z

On Fri, Apr 10, 2026 at 05:33:48PM +0800, Yongxing Mou wrote:
> From: Abhinav Kumar <quic_abhinavk@quicinc.com>
>
> With MST, each DP controller can handle multiple streams.
> There shall be one dp_panel for each stream but the dp_display
> object shall be shared among them. To represent this abstraction,
> create a stream_id for each DP panel which shall be set by the
> MST stream. For SST, default this to stream 0.
>
> Use the stream ID to control the pixel clock of that respective
> stream by extending the clock handles and state tracking of the
> DP pixel clock to an array of max supported streams. The maximum
> streams currently is 4.
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
> ---
> drivers/gpu/drm/msm/dp/dp_ctrl.c | 57 +++++++++++++++++++++++--------------
> drivers/gpu/drm/msm/dp/dp_ctrl.h | 2 +-
> drivers/gpu/drm/msm/dp/dp_display.c | 24 ++++++++++++++--
> drivers/gpu/drm/msm/dp/dp_display.h | 2 ++
> drivers/gpu/drm/msm/dp/dp_panel.h | 11 +++++++
> 5 files changed, 71 insertions(+), 25 deletions(-)
> @@ -2735,9 +2740,17 @@ static int msm_dp_ctrl_clk_init(struct msm_dp_ctrl *msm_dp_ctrl)
> if (rc)
> return rc;
>
> - ctrl->pixel_clk = devm_clk_get(dev, "stream_pixel");
> - if (IS_ERR(ctrl->pixel_clk))
> - return PTR_ERR(ctrl->pixel_clk);
> + for (i = DP_STREAM_0; i < DP_STREAM_MAX; i++) {
> + ctrl->pixel_clk[i] = devm_clk_get(dev, pixel_clks[i]);
> +
> + if (i == 0 && IS_ERR(ctrl->pixel_clk[i]))
> + return PTR_ERR(ctrl->pixel_clk[i]);
> +
> + if (IS_ERR(ctrl->pixel_clk[i])) {
> + DRM_DEBUG_DP("stream %d pixel clock not exist", i);
> + break;
> + }

Almost missed it. If it is -EPROBE_DEFER, we must return an error. In
fact, I'd rather check for -ENOENT (or is it -ENODEV?) and pass all
other errors to the caller.

> + }
>
> return 0;
> }

--
With best wishes
Dmitry