This patch implemnets Workariunds related to display arbitrated memory
bandwidth. These WA are applicabe for all gen-9 based platforms.

Changes since v1:
 - Rebase on top of Paulo's patch series
Changes since v2:
 - Rebase/rework after addressing Paulo's comments in previous patch

Signed-off-by: "Kumar, Mahesh" <mahesh1.ku...@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |   9 +++
 drivers/gpu/drm/i915/intel_drv.h |  11 +++
 drivers/gpu/drm/i915/intel_pm.c  | 146 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 166 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index adbd9aa..c169360 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1092,6 +1092,13 @@ enum intel_sbi_destination {
        SBI_MPHY,
 };
 
+/* SKL+ Watermark arbitrated display bandwidth Workarounds */
+enum watermark_memory_wa {
+       WATERMARK_WA_NONE,
+       WATERMARK_WA_X_TILED,
+       WATERMARK_WA_Y_TILED,
+};
+
 #define QUIRK_PIPEA_FORCE (1<<0)
 #define QUIRK_LVDS_SSC_DISABLE (1<<1)
 #define QUIRK_INVERT_BRIGHTNESS (1<<2)
@@ -1644,6 +1651,8 @@ struct skl_ddb_allocation {
 
 struct skl_wm_values {
        unsigned dirty_pipes;
+       /* any WaterMark memory workaround Required */
+       enum watermark_memory_wa mem_wa;
        struct skl_ddb_allocation ddb;
        uint32_t wm_linetime[I915_MAX_PIPES];
        uint32_t plane[I915_MAX_PIPES][I915_MAX_PLANES][8];
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f48e79a..2c1897b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1813,6 +1813,17 @@ intel_atomic_get_crtc_state(struct drm_atomic_state 
*state,
        return to_intel_crtc_state(crtc_state);
 }
 
+static inline struct intel_crtc_state *
+intel_atomic_get_existing_crtc_state(struct drm_atomic_state *state,
+                                     struct intel_crtc *crtc)
+{
+       struct drm_crtc_state *crtc_state;
+
+       crtc_state = drm_atomic_get_existing_crtc_state(state, &crtc->base);
+
+       return to_intel_crtc_state(crtc_state);
+}
+
 static inline struct intel_plane_state *
 intel_atomic_get_existing_plane_state(struct drm_atomic_state *state,
                                      struct intel_plane *plane)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 84ec6b1..5b8f715 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3589,6 +3589,8 @@ static int skl_compute_plane_wm(const struct 
drm_i915_private *dev_priv,
 {
        struct drm_plane_state *pstate = &intel_pstate->base;
        struct drm_framebuffer *fb = pstate->fb;
+       struct intel_atomic_state *intel_state =
+                       to_intel_atomic_state(cstate->base.state);
        uint32_t latency = dev_priv->wm.skl_latency[level];
        uint32_t method1, method2;
        uint32_t plane_bytes_per_line, plane_blocks_per_line;
@@ -3598,10 +3600,17 @@ static int skl_compute_plane_wm(const struct 
drm_i915_private *dev_priv,
        uint32_t width = 0, height = 0;
        uint32_t plane_pixel_rate;
        uint32_t y_tile_minimum, y_min_scanlines;
+       enum watermark_memory_wa mem_wa;
 
        if (latency == 0 || !cstate->base.active || !intel_pstate->base.visible)
                return 0;
 
+       mem_wa = intel_state ? intel_state->wm_results.mem_wa : 
WATERMARK_WA_NONE;
+       if (mem_wa != WATERMARK_WA_NONE) {
+               if (fb->modifier[0] == I915_FORMAT_MOD_X_TILED)
+                       latency += 15;
+       }
+
        width = drm_rect_width(&intel_pstate->base.src) >> 16;
        height = drm_rect_height(&intel_pstate->base.src) >> 16;
 
@@ -3634,6 +3643,9 @@ static int skl_compute_plane_wm(const struct 
drm_i915_private *dev_priv,
                y_min_scanlines = 4;
        }
 
+       if (mem_wa == WATERMARK_WA_Y_TILED)
+               y_min_scanlines *= 2;
+
        plane_bytes_per_line = width * cpp;
        if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
            fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {
@@ -4075,6 +4087,15 @@ skl_include_affected_pipes(struct drm_atomic_state 
*state)
                intel_state->wm_results.dirty_pipes = ~0;
        }
 
+       /*
+        * If Watermark workaround is changed we need to recalculate
+        * watermark values for all active pipes
+        */
+       if (intel_state->wm_results.mem_wa != dev_priv->wm.skl_hw.mem_wa) {
+               realloc_pipes = ~0;
+               intel_state->wm_results.dirty_pipes = ~0;
+       }
+
        for_each_intel_crtc_mask(dev, intel_crtc, realloc_pipes) {
                struct intel_crtc_state *cstate;
 
@@ -4087,6 +4108,129 @@ skl_include_affected_pipes(struct drm_atomic_state 
*state)
 }
 
 static void
+skl_set_memory_bandwidth_wm_wa(struct drm_atomic_state *state)
+{
+       struct drm_device *dev = state->dev;
+       struct drm_i915_private *dev_priv = to_i915(dev);
+       struct intel_crtc *intel_crtc;
+       struct intel_plane_state *intel_pstate;
+       struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
+       struct memdev_info *memdev_info = &dev_priv->memdev_info;
+       int num_active_plane, num_active_pipe;
+       uint32_t plane_bw, max_plane_bw, pipe_bw, max_pipe_bw;
+       uint32_t total_pipe_bw;
+       uint32_t system_bw = 0;
+       uint32_t rank;
+       int x_tile_per;
+       int display_bw_per;
+       bool y_tile_enabled = false;
+
+       if (!memdev_info->valid)
+               goto exit;
+
+       system_bw = memdev_info->mem_speed_khz * memdev_info->num_channels *
+                               memdev_info->channel_width_bytes;
+
+       if (!system_bw)
+               goto exit;
+
+       max_pipe_bw = 0;
+       for_each_intel_crtc(dev, intel_crtc) {
+               struct intel_crtc_state *cstate;
+               struct intel_plane *plane;
+
+               /*
+                * If CRTC is part of current atomic commit, get crtc state from
+                * existing CRTC state. else take the cached CRTC state
+                */
+               cstate = NULL;
+               if (state)
+                       cstate = intel_atomic_get_existing_crtc_state(state,
+                                       intel_crtc);
+               if (!cstate)
+                       cstate = to_intel_crtc_state(intel_crtc->base.state);
+
+               if (!cstate->base.active)
+                       continue;
+
+               num_active_plane = 0;
+               max_plane_bw = 0;
+               for_each_intel_plane_mask(dev, plane, cstate->base.plane_mask) {
+                       struct drm_framebuffer *fb = NULL;
+
+                       intel_pstate = NULL;
+                       if (state)
+                               intel_pstate =
+                               intel_atomic_get_existing_plane_state(state,
+                                                                       plane);
+                       if (!intel_pstate)
+                               intel_pstate =
+                                       to_intel_plane_state(plane->base.state);
+
+                       WARN_ON(!intel_pstate->base.fb);
+
+                       if (!intel_pstate->base.visible)
+                               continue;
+
+                       fb = intel_pstate->base.fb;
+                       if (fb && (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
+                               fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED))
+                               y_tile_enabled = true;
+
+                       plane_bw = skl_adjusted_plane_pixel_rate(cstate,
+                                                               intel_pstate);
+                       max_plane_bw = max(plane_bw, max_plane_bw);
+                       num_active_plane++;
+               }
+               pipe_bw = max_plane_bw * num_active_plane;
+               max_pipe_bw = max(pipe_bw, max_pipe_bw);
+       }
+
+       if (intel_state->active_pipe_changes)
+               num_active_pipe = hweight32(intel_state->active_crtcs);
+       else
+               num_active_pipe = hweight32(dev_priv->active_crtcs);
+
+       total_pipe_bw = max_pipe_bw * num_active_pipe;
+
+       display_bw_per = DIV_ROUND_UP_ULL(total_pipe_bw * 100, system_bw * 
1000);
+
+       /*
+        * If there is any Ytile plane enabled and arbitrated display
+        * bandwidth > 20% of raw system memory bandwidth
+        * Enale Y-tile related WA
+        *
+        * If memory is dual channel single rank, Xtile limit = 35%, else Xtile
+        * limit = 60%
+        * If there is no Ytile plane enabled and
+        * arbitrated display bandwidth > Xtile limit
+        * Enable X-tile realated WA
+        */
+       if (y_tile_enabled && (display_bw_per > 20))
+               intel_state->wm_results.mem_wa = WATERMARK_WA_Y_TILED;
+       else {
+
+               if (memdev_info->rank_valid)
+                       rank = memdev_info->rank;
+               else
+                       rank = DRAM_RANK_DUAL; /* Assume we are dual rank */
+
+               if ((rank == DRAM_RANK_SINGLE) &&
+                                       (memdev_info->num_channels == 2))
+                       x_tile_per = 35;
+               else
+                       x_tile_per = 60;
+
+               if (display_bw_per > x_tile_per)
+                       intel_state->wm_results.mem_wa = WATERMARK_WA_X_TILED;
+       }
+       return;
+
+exit:
+       intel_state->wm_results.mem_wa = WATERMARK_WA_NONE;
+}
+
+static void
 skl_copy_wm_for_pipe(struct skl_wm_values *dst,
                     struct skl_wm_values *src,
                     enum pipe pipe)
@@ -4131,6 +4275,8 @@ skl_compute_wm(struct drm_atomic_state *state)
        /* Clear all dirty flags */
        results->dirty_pipes = 0;
 
+       skl_set_memory_bandwidth_wm_wa(state);
+
        ret = skl_include_affected_pipes(state);
        if (ret)
                return ret;
-- 
2.10.1

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