drm_panic draws in linear framebuffer, so it's easier to re-use the
current framebuffer, and disable tiling in the panic handler, to show
the panic screen.

Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
---
 drivers/gpu/drm/i915/display/i9xx_plane.c     | 23 +++++++++++++++++++
 .../drm/i915/display/intel_display_types.h    |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c
index 17a1e3801a85c..671d3914585bf 100644
--- a/drivers/gpu/drm/i915/display/i9xx_plane.c
+++ b/drivers/gpu/drm/i915/display/i9xx_plane.c
@@ -848,6 +848,27 @@ static const struct drm_plane_funcs i8xx_plane_funcs = {
 	.format_mod_supported = i8xx_plane_format_mod_supported,
 };
 
+static void i9xx_disable_tiling(struct intel_plane *plane)
+{
+	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
+	enum i9xx_plane_id i9xx_plane = plane->i9xx_plane;
+	u32 dspcntr;
+	u32 reg;
+
+	dspcntr = intel_de_read_fw(dev_priv, DSPCNTR(dev_priv, i9xx_plane));
+	dspcntr &= ~DISP_TILED;
+	intel_de_write_fw(dev_priv, DSPCNTR(dev_priv, i9xx_plane), dspcntr);
+
+	if (DISPLAY_VER(dev_priv) >= 4) {
+		reg = intel_de_read_fw(dev_priv, DSPSURF(dev_priv, i9xx_plane));
+		intel_de_write_fw(dev_priv, DSPSURF(dev_priv, i9xx_plane), reg);
+
+	} else {
+		reg = intel_de_read_fw(dev_priv, DSPADDR(dev_priv, i9xx_plane));
+		intel_de_write_fw(dev_priv, DSPADDR(dev_priv, i9xx_plane), reg);
+	}
+}
+
 struct intel_plane *
 intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
 {
@@ -973,6 +994,8 @@ intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
 		plane->disable_flip_done = ilk_primary_disable_flip_done;
 	}
 
+	plane->disable_tiling = i9xx_disable_tiling;
+
 	modifiers = intel_fb_plane_get_modifiers(dev_priv, INTEL_PLANE_CAP_TILING_X);
 
 	if (DISPLAY_VER(dev_priv) >= 5 || IS_G4X(dev_priv))
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index ff6eb93337e0a..31804fb99e168 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1482,6 +1482,8 @@ struct intel_plane {
 			   bool async_flip);
 	void (*enable_flip_done)(struct intel_plane *plane);
 	void (*disable_flip_done)(struct intel_plane *plane);
+	/* For drm_panic */
+	void (*disable_tiling)(struct intel_plane *plane);
 };
 
 #define to_intel_atomic_state(x) container_of(x, struct intel_atomic_state, base)
-- 
2.47.1