drm/i915/dp: Introduce helper to check pixel rate against dotclock limits

Add intel_dp_dotclk_valid() helper, that checks the required pixel rate
against platform dotclock limit. With joined pipes the effective dotclock
limit depends upon the number of joined pipes.

Call the helper from the mode_valid phase and from the compute_config
phase where we need to check the limits for the given target clock for a
given joiner candidate.

v2: Rename the helper to intel_dp_dotclk_valid(). (Imre)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20260202103731.357416-13-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 6a4edf1538a6f97e9d900b4714d207b842b85261..95992172b780700b8d0d55b8c21685d863b3c753 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1412,6 +1412,18 @@ bool intel_dp_can_join(struct intel_display *display,
        }
 }
 
+bool intel_dp_dotclk_valid(struct intel_display *display,
+                          int target_clock,
+                          int num_joined_pipes)
+{
+       int max_dotclk = display->cdclk.max_dotclk_freq;
+       int effective_dotclk_limit;
+
+       effective_dotclk_limit = max_dotclk * num_joined_pipes;
+
+       return target_clock <= effective_dotclk_limit;
+}
+
 static enum drm_mode_status
 intel_dp_mode_valid(struct drm_connector *_connector,
                    const struct drm_display_mode *mode)
@@ -1474,8 +1486,6 @@ intel_dp_mode_valid(struct drm_connector *_connector,
         */
        status = MODE_CLOCK_HIGH;
        for (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
-               int max_dotclk = display->cdclk.max_dotclk_freq;
-
                if (connector->force_joined_pipes &&
                    num_joined_pipes != connector->force_joined_pipes)
                        continue;
@@ -1543,9 +1553,9 @@ intel_dp_mode_valid(struct drm_connector *_connector,
                if (status != MODE_OK)
                        continue;
 
-               max_dotclk *= num_joined_pipes;
-
-               if (target_clock > max_dotclk) {
+               if (!intel_dp_dotclk_valid(display,
+                                          target_clock,
+                                          num_joined_pipes)) {
                        status = MODE_CLOCK_HIGH;
                        continue;
                }
@@ -2776,12 +2786,10 @@ intel_dp_compute_link_for_joined_pipes(struct intel_encoder *encoder,
        const struct drm_display_mode *adjusted_mode =
                &pipe_config->hw.adjusted_mode;
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
-       int max_dotclk = display->cdclk.max_dotclk_freq;
        struct link_config_limits limits;
        bool dsc_needed, joiner_needs_dsc;
        int ret = 0;
 
-       max_dotclk *= num_joined_pipes;
        joiner_needs_dsc = intel_dp_joiner_needs_dsc(display, num_joined_pipes);
 
        dsc_needed = joiner_needs_dsc || intel_dp->force_dsc_en ||
@@ -2805,7 +2813,10 @@ intel_dp_compute_link_for_joined_pipes(struct intel_encoder *encoder,
                                                             fxp_q4_from_int(pipe_config->pipe_bpp),
                                                             0, false);
 
-               if (ret || adjusted_mode->crtc_clock > max_dotclk)
+               if (ret ||
+                   !intel_dp_dotclk_valid(display,
+                                          adjusted_mode->crtc_clock,
+                                          num_joined_pipes))
                        dsc_needed = true;
        }
 
@@ -2831,7 +2842,9 @@ intel_dp_compute_link_for_joined_pipes(struct intel_encoder *encoder,
                if (ret < 0)
                        return ret;
 
-               if (adjusted_mode->crtc_clock > max_dotclk)
+               if (!intel_dp_dotclk_valid(display,
+                                          adjusted_mode->crtc_clock,
+                                          num_joined_pipes))
                        return -EINVAL;
        }
 

diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index ebaa35d23c9c3c134d666864789d925a507c47fd..edeb09372d1e7ed301ab13e7af28c0367fbe41de 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -224,5 +224,8 @@ int intel_dp_sdp_min_guardband(const struct intel_crtc_state *crtc_state,
 int intel_dp_max_hdisplay_per_pipe(struct intel_display *display);
 bool intel_dp_can_join(struct intel_display *display,
                       int num_joined_pipes);
+bool intel_dp_dotclk_valid(struct intel_display *display,
+                          int target_clock,
+                          int num_joined_pipes);
 
 #endif /* __INTEL_DP_H__ */

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 634720fec612ef5ecbb2b45f433dcc22c3409eb5..83fe389ea2dcfa49633586d494b2e6996a421aff 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -606,12 +606,10 @@ static int mst_stream_compute_link_for_joined_pipes(struct intel_encoder *encode
                &pipe_config->hw.adjusted_mode;
        struct intel_connector *connector =
                to_intel_connector(conn_state->connector);
-       int max_dotclk = display->cdclk.max_dotclk_freq;
        struct link_config_limits limits;
        bool dsc_needed, joiner_needs_dsc;
        int ret = 0;
 
-       max_dotclk *= num_joined_pipes;
        joiner_needs_dsc = intel_dp_joiner_needs_dsc(display, num_joined_pipes);
 
        dsc_needed = joiner_needs_dsc || intel_dp->force_dsc_en ||
@@ -625,7 +623,10 @@ static int mst_stream_compute_link_for_joined_pipes(struct intel_encoder *encode
                if (ret == -EDEADLK)
                        return ret;
 
-               if (ret || adjusted_mode->clock > max_dotclk)
+               if (ret ||
+                   !intel_dp_dotclk_valid(display,
+                                          adjusted_mode->clock,
+                                          num_joined_pipes))
                        dsc_needed = true;
        }
 
@@ -669,7 +670,9 @@ static int mst_stream_compute_link_for_joined_pipes(struct intel_encoder *encode
                if (ret)
                        return ret;
 
-               if (adjusted_mode->clock > max_dotclk)
+               if (!intel_dp_dotclk_valid(display,
+                                          adjusted_mode->clock,
+                                          num_joined_pipes))
                        return -EINVAL;
        }
 
@@ -1525,8 +1528,6 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
 
        *status = MODE_CLOCK_HIGH;
        for (num_joined_pipes = 1; num_joined_pipes <= I915_MAX_PIPES; num_joined_pipes++) {
-               int max_dotclk = display->cdclk.max_dotclk_freq;
-
                if (connector->force_joined_pipes &&
                    num_joined_pipes != connector->force_joined_pipes)
                        continue;
@@ -1571,9 +1572,9 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
                if (*status != MODE_OK)
                        continue;
 
-               max_dotclk *= num_joined_pipes;
-
-               if (mode->clock > max_dotclk) {
+               if (!intel_dp_dotclk_valid(display,
+                                          mode->clock,
+                                          num_joined_pipes)) {
                        *status = MODE_CLOCK_HIGH;
                        continue;
                }