drm/amd/display: use proper formula to calculate bandwidth from timing

[why]
The existing calculation uses a wrong formula to
calculate bandwidth from timing.

[how]
Expose the existing proper function that calculates the bandwidth,
so dc_link can use it to calculate timing bandwidth correctly.

Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index 2f0117c..abf6115 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -2321,7 +2321,7 @@ static struct fixed31_32 get_pbn_from_timing(struct pipe_ctx *pipe_ctx)
        uint32_t denominator;
 
        bpc = get_color_depth(pipe_ctx->stream_res.pix_clk_params.color_depth);
-       kbps = pipe_ctx->stream_res.pix_clk_params.requested_pix_clk_100hz / 10 * bpc * 3;
+       kbps = dc_bandwidth_in_kbps_from_timing(&pipe_ctx->stream->timing);
 
        /*
         * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
@@ -2736,3 +2736,49 @@ void dc_link_enable_hpd_filter(struct dc_link *link, bool enable)
        }
 }
 
+uint32_t dc_bandwidth_in_kbps_from_timing(
+       const struct dc_crtc_timing *timing)
+{
+       uint32_t bits_per_channel = 0;
+       uint32_t kbps;
+
+       switch (timing->display_color_depth) {
+       case COLOR_DEPTH_666:
+               bits_per_channel = 6;
+               break;
+       case COLOR_DEPTH_888:
+               bits_per_channel = 8;
+               break;
+       case COLOR_DEPTH_101010:
+               bits_per_channel = 10;
+               break;
+       case COLOR_DEPTH_121212:
+               bits_per_channel = 12;
+               break;
+       case COLOR_DEPTH_141414:
+               bits_per_channel = 14;
+               break;
+       case COLOR_DEPTH_161616:
+               bits_per_channel = 16;
+               break;
+       default:
+               break;
+       }
+
+       ASSERT(bits_per_channel != 0);
+
+       kbps = timing->pix_clk_100hz / 10;
+       kbps *= bits_per_channel;
+
+       if (timing->flags.Y_ONLY != 1) {
+               /*Only YOnly make reduce bandwidth by 1/3 compares to RGB*/
+               kbps *= 3;
+               if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420)
+                       kbps /= 2;
+               else if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR422)
+                       kbps = kbps * 2 / 3;
+       }
+
+       return kbps;
+
+}

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 528c962..491d13d 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -1533,53 +1533,6 @@ static bool decide_fallback_link_setting(
        return true;
 }
 
-static uint32_t bandwidth_in_kbps_from_timing(
-       const struct dc_crtc_timing *timing)
-{
-       uint32_t bits_per_channel = 0;
-       uint32_t kbps;
-
-       switch (timing->display_color_depth) {
-       case COLOR_DEPTH_666:
-               bits_per_channel = 6;
-               break;
-       case COLOR_DEPTH_888:
-               bits_per_channel = 8;
-               break;
-       case COLOR_DEPTH_101010:
-               bits_per_channel = 10;
-               break;
-       case COLOR_DEPTH_121212:
-               bits_per_channel = 12;
-               break;
-       case COLOR_DEPTH_141414:
-               bits_per_channel = 14;
-               break;
-       case COLOR_DEPTH_161616:
-               bits_per_channel = 16;
-               break;
-       default:
-               break;
-       }
-
-       ASSERT(bits_per_channel != 0);
-
-       kbps = timing->pix_clk_100hz / 10;
-       kbps *= bits_per_channel;
-
-       if (timing->flags.Y_ONLY != 1) {
-               /*Only YOnly make reduce bandwidth by 1/3 compares to RGB*/
-               kbps *= 3;
-               if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420)
-                       kbps /= 2;
-               else if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR422)
-                       kbps = kbps * 2 / 3;
-       }
-
-       return kbps;
-
-}
-
 static uint32_t bandwidth_in_kbps_from_link_settings(
        const struct dc_link_settings *link_setting)
 {
@@ -1620,7 +1573,7 @@ bool dp_validate_mode_timing(
                link_setting = &link->verified_link_cap;
        */
 
-       req_bw = bandwidth_in_kbps_from_timing(timing);
+       req_bw = dc_bandwidth_in_kbps_from_timing(timing);
        max_bw = bandwidth_in_kbps_from_link_settings(link_setting);
 
        if (req_bw <= max_bw) {
@@ -1739,7 +1692,7 @@ void decide_link_settings(struct dc_stream_state *stream,
        struct dc_link *link;
        uint32_t req_bw;
 
-       req_bw = bandwidth_in_kbps_from_timing(&stream->timing);
+       req_bw = dc_bandwidth_in_kbps_from_timing(&stream->timing);
 
        link = stream->link;
 

diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index 8fc223d..a83e1c6 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -252,4 +252,6 @@ bool dc_submit_i2c(
                uint32_t link_index,
                struct i2c_command *cmd);
 
+uint32_t dc_bandwidth_in_kbps_from_timing(
+       const struct dc_crtc_timing *timing);
 #endif /* DC_LINK_H_ */