On Mon, Aug 25, 2025 at 10:15:51PM +0800, Yongxing Mou wrote:
> The DP_CONFIGURATION_CTRL register contains both link-level and
> stream-specific fields. Currently, msm_dp_ctrl_config_ctrl() configures
> all of them together, which makes it harder to support MST.
>
> This patch separates the configuration into two functions:
git grep "This patch" Documentation/process
> - msm_dp_ctrl_config_ctrl_link(): handles link-related fields
> - msm_dp_ctrl_config_ctrl_streams(): handles stream-specific fields
>
> It also moves the link-related configuration out of
> msm_dp_ctrl_configure_source_params().
Why? And it looks like a separate patch...
>
> Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/dp/dp_ctrl.c | 49 +++++++++++++++++++++++++---------------
> 1 file changed, 31 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index e1ff4c6bb4f0eed2e1ff931f12ba891cf81feffb..45d6c9a7f7ddaa049443253cbf4c6fc5feda3177 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -380,26 +380,41 @@ void msm_dp_ctrl_push_idle(struct msm_dp_ctrl *msm_dp_ctrl)
> drm_dbg_dp(ctrl->drm_dev, "mainlink off\n");
> }
>
> -static void msm_dp_ctrl_config_ctrl(struct msm_dp_ctrl_private *ctrl)
> +static void msm_dp_ctrl_config_ctrl_streams(struct msm_dp_ctrl_private *ctrl,
> + struct msm_dp_panel *msm_dp_panel)
> {
> u32 config = 0, tbd;
> +
> + config = msm_dp_read_link(ctrl, REG_DP_CONFIGURATION_CTRL);
> +
> + if (msm_dp_panel->msm_dp_mode.out_fmt_is_yuv_420)
> + config |= DP_CONFIGURATION_CTRL_RGB_YUV; /* YUV420 */
> +
> + tbd = msm_dp_link_get_test_bits_depth(ctrl->link,
> + msm_dp_panel->msm_dp_mode.bpp);
> +
> + config |= tbd << DP_CONFIGURATION_CTRL_BPC_SHIFT;
> +
> + if (msm_dp_panel->psr_cap.version)
> + config |= DP_CONFIGURATION_CTRL_SEND_VSC;
> +
> + drm_dbg_dp(ctrl->drm_dev, "stream DP_CONFIGURATION_CTRL=0x%x\n", config);
> +
> + msm_dp_write_link(ctrl, REG_DP_CONFIGURATION_CTRL, config);
> +}
> +
> +static void msm_dp_ctrl_config_ctrl_link(struct msm_dp_ctrl_private *ctrl)
> +{
> + u32 config = 0;
> const u8 *dpcd = ctrl->panel->dpcd;
>
> /* Default-> LSCLK DIV: 1/4 LCLK */
> config |= (2 << DP_CONFIGURATION_CTRL_LSCLK_DIV_SHIFT);
>
> - if (ctrl->panel->msm_dp_mode.out_fmt_is_yuv_420)
> - config |= DP_CONFIGURATION_CTRL_RGB_YUV; /* YUV420 */
> -
> /* Scrambler reset enable */
> if (drm_dp_alternate_scrambler_reset_cap(dpcd))
> config |= DP_CONFIGURATION_CTRL_ASSR;
>
> - tbd = msm_dp_link_get_test_bits_depth(ctrl->link,
> - ctrl->panel->msm_dp_mode.bpp);
> -
> - config |= tbd << DP_CONFIGURATION_CTRL_BPC_SHIFT;
> -
> /* Num of Lanes */
> config |= ((ctrl->link->link_params.num_lanes - 1)
> << DP_CONFIGURATION_CTRL_NUM_OF_LANES_SHIFT);
> @@ -413,10 +428,7 @@ static void msm_dp_ctrl_config_ctrl(struct msm_dp_ctrl_private *ctrl)
> config |= DP_CONFIGURATION_CTRL_STATIC_DYNAMIC_CN;
> config |= DP_CONFIGURATION_CTRL_SYNC_ASYNC_CLK;
>
> - if (ctrl->panel->psr_cap.version)
> - config |= DP_CONFIGURATION_CTRL_SEND_VSC;
> -
> - drm_dbg_dp(ctrl->drm_dev, "DP_CONFIGURATION_CTRL=0x%x\n", config);
> + drm_dbg_dp(ctrl->drm_dev, "link DP_CONFIGURATION_CTRL=0x%x\n", config);
>
> msm_dp_write_link(ctrl, REG_DP_CONFIGURATION_CTRL, config);
> }
> @@ -439,10 +451,7 @@ static void msm_dp_ctrl_configure_source_params(struct msm_dp_ctrl_private *ctrl
> {
> u32 colorimetry_cfg, test_bits_depth, misc_val;
>
> - msm_dp_ctrl_lane_mapping(ctrl);
> - msm_dp_setup_peripheral_flush(ctrl);
> -
> - msm_dp_ctrl_config_ctrl(ctrl);
> + msm_dp_ctrl_config_ctrl_streams(ctrl, ctrl->panel);
>
> test_bits_depth = msm_dp_link_get_test_bits_depth(ctrl->link, ctrl->panel->msm_dp_mode.bpp);
> colorimetry_cfg = msm_dp_link_get_colorimetry_config(ctrl->link);
> @@ -1614,7 +1623,7 @@ static int msm_dp_ctrl_link_train(struct msm_dp_ctrl_private *ctrl,
> u8 assr;
> struct msm_dp_link_info link_info = {0};
>
> - msm_dp_ctrl_config_ctrl(ctrl);
> + msm_dp_ctrl_config_ctrl_link(ctrl);
>
> link_info.num_lanes = ctrl->link->link_params.num_lanes;
> link_info.rate = ctrl->link->link_params.rate;
> @@ -2524,6 +2533,10 @@ int msm_dp_ctrl_on_stream(struct msm_dp_ctrl *msm_dp_ctrl)
> */
> reinit_completion(&ctrl->video_comp);
>
> + msm_dp_ctrl_lane_mapping(ctrl);
> + msm_dp_setup_peripheral_flush(ctrl);
> + msm_dp_ctrl_config_ctrl_link(ctrl);
> +
> msm_dp_ctrl_configure_source_params(ctrl);
>
> msm_dp_ctrl_config_msa(ctrl,
>
> --
> 2.34.1
>
--
With best wishes
Dmitry
