drm/i915: Compute display surface offset in the plane check hook for SKL+

SKL has nasty limitations with the display surface offsets:
* source x offset + width must be less than the stride for X tiled
  surfaces or the display engine falls over
* the surface offset requires lots of alignment (256K or 1M)

These facts mean that we can't just pick any suitably aligned tile
boundary as the offset and expect the resulting x offset to be useable.
The solution is to start with the closest boundary as before, but then
keep searching backwards until we find one that works, or don't. This
means we must be prepared to fail, hence the whole surface offset
calculation needs to be moved to the .check_plane() hook from the
.update_plane() hook.

While at it we can check that the source width/height don't exceed
maximum plane size limits.

We'll store the results of the computation in the plane state to make
it easy for the .update_plane() hook to do its thing.

v2: Replace for+break loop with while loop
    Rebase due to drm_plane_state src/dst rects
    Rebase due to plane_check_state()

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470821001-25272-11-git-send-email-ville.syrjala@linux.intel.com

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 9b27bd7f7283..2b980f7855d4 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -353,6 +353,11 @@ struct intel_plane_state {
 	struct drm_rect clip;
 	bool visible;
 
+	struct {
+		u32 offset;
+		int x, y;
+	} main;
+
 	/*
 	 * scaler_id
 	 *    = -1 : not using a scaler
@@ -1346,6 +1351,7 @@ u32 skl_plane_ctl_tiling(uint64_t fb_modifier);
 u32 skl_plane_ctl_rotation(unsigned int rotation);
 u32 skl_plane_stride(const struct drm_framebuffer *fb, int plane,
 		     unsigned int rotation);
+int skl_check_plane_surface(struct intel_plane_state *plane_state);
 
 /* intel_csr.c */
 void intel_csr_ucode_init(struct drm_i915_private *);