drm/i915/gen9: minimum scanlines for Y tile is not always 4

During watermarks calculations, this value is used in 3 different
places. Only one of them was not using a hardcoded 4. Move the code up
so everybody can benefit from the actual value.

This should only help on situations with Y tiling + 90/270 rotation +
1 or 2 bpp or NV12.

Cc: stable@vger.kernel.org
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1474578035-424-6-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit 1186fa85eb9b3cc0589990fbc39617e50e38759a)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 32 insertions, 24 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c90be917deae..32ce9365d763 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3495,7 +3495,8 @@ static uint32_t skl_wm_method1(uint32_t pixel_rate, uint8_t cpp, uint32_t latenc
 
 static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
                                uint32_t horiz_pixels, uint8_t cpp,
-                               uint64_t tiling, uint32_t latency)
+                               uint64_t tiling, uint32_t latency,
+                               uint32_t y_min_scanlines)
 {
         uint32_t ret;
         uint32_t plane_bytes_per_line, plane_blocks_per_line;
@@ -3508,9 +3509,9 @@ static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
 
         if (tiling == I915_FORMAT_MOD_Y_TILED ||
             tiling == I915_FORMAT_MOD_Yf_TILED) {
-                plane_bytes_per_line *= 4;
+                plane_bytes_per_line *= y_min_scanlines;
                 plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
-                plane_blocks_per_line /= 4;
+                plane_blocks_per_line /= y_min_scanlines;
         } else if (tiling == DRM_FORMAT_MOD_NONE) {
                 plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
         } else {
@@ -3567,6 +3568,7 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
         uint8_t cpp;
         uint32_t width = 0, height = 0;
         uint32_t plane_pixel_rate;
+        uint32_t y_min_scanlines;
 
         if (latency == 0 || !cstate->base.active || !intel_pstate->base.visible) {
                 *enabled = false;
@@ -3582,38 +3584,44 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
         cpp = drm_format_plane_cpp(fb->pixel_format, 0);
         plane_pixel_rate = skl_adjusted_plane_pixel_rate(cstate, intel_pstate);
 
+        if (intel_rotation_90_or_270(pstate->rotation)) {
+                int cpp = (fb->pixel_format == DRM_FORMAT_NV12) ?
+                        drm_format_plane_cpp(fb->pixel_format, 1) :
+                        drm_format_plane_cpp(fb->pixel_format, 0);
+
+                switch (cpp) {
+                case 1:
+                        y_min_scanlines = 16;
+                        break;
+                case 2:
+                        y_min_scanlines = 8;
+                        break;
+                default:
+                        WARN(1, "Unsupported pixel depth for rotation");
+                case 4:
+                        y_min_scanlines = 4;
+                        break;
+                }
+        } else {
+                y_min_scanlines = 4;
+        }
+
         method1 = skl_wm_method1(plane_pixel_rate, cpp, latency);
         method2 = skl_wm_method2(plane_pixel_rate,
                                  cstate->base.adjusted_mode.crtc_htotal,
                                  width,
                                  cpp,
                                  fb->modifier[0],
-                                 latency);
+                                 latency,
+                                 y_min_scanlines);
 
         plane_bytes_per_line = width * cpp;
         plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
 
         if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
             fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {
-                uint32_t min_scanlines = 4;
-                uint32_t y_tile_minimum;
-                if (intel_rotation_90_or_270(pstate->rotation)) {
-                        int cpp = (fb->pixel_format == DRM_FORMAT_NV12) ?
-                                drm_format_plane_cpp(fb->pixel_format, 1) :
-                                drm_format_plane_cpp(fb->pixel_format, 0);
-
-                        switch (cpp) {
-                        case 1:
-                                min_scanlines = 16;
-                                break;
-                        case 2:
-                                min_scanlines = 8;
-                                break;
-                        case 8:
-                                WARN(1, "Unsupported pixel depth for rotation");
-                        }
-                }
-                y_tile_minimum = plane_blocks_per_line * min_scanlines;
+                uint32_t y_tile_minimum = plane_blocks_per_line *
+                                          y_min_scanlines;
                 selected_result = max(method2, y_tile_minimum);
         } else {
                 if ((ddb_allocation / plane_blocks_per_line) >= 1)
@@ -3628,7 +3636,7 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
         if (level >= 1 && level <= 7) {
                 if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED ||
                     fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED)
-                        res_lines += 4;
+                        res_lines += y_min_scanlines;
                 else
                         res_blocks++;
         }