[Intel-gfx] [PATCH] drm/i915: Align initial plane backing objects correctly

[Daniel Vetter]

Some bios really like to joke and start the planes at an offset ...
hooray!

Align start and end to fix this.

v2: Fixup calculation of size, spotted by Chris Wilson.

v3: Fix serious fumble I've just spotted.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86883
Cc: stable at vger.kernel.org
Cc: Johannes W <jargon at molb.org>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Reported-by: Johannes W <jargon at molb.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

--

Johannes, can you please test this patch instead of the one from
Chris?

Thanks, Daniel
---
 drivers/gpu/drm/i915/i915_gem_stolen.c |  5 +----
 drivers/gpu/drm/i915/intel_display.c   | 18 ++++++++++++------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 59401f3b902c..4382696087c9 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -485,10 +485,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 			stolen_offset, gtt_offset, size);
 
 	/* KISS and expect everything to be page-aligned */
-	BUG_ON(stolen_offset & 4095);
-	BUG_ON(size & 4095);
-
-	if (WARN_ON(size == 0))
+	if (WARN_ON(size == 0 || stolen_offset & 4095 || size & 4095))
 		return NULL;
 
 	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2655b63d65e9..fc855b9548ec 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2372,13 +2372,19 @@ intel_alloc_plane_obj(struct intel_crtc *crtc,
 	struct drm_i915_gem_object *obj = NULL;
 	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
 	struct drm_framebuffer *fb = &plane_config->fb->base;
-	u32 base = plane_config->base;
+	u32 base_aligned = round_down(plane_config->base, PAGE_SIZE);
+	u32 size_aligned = round_up(plane_config->base + plane_config->size,
+				    PAGE_SIZE);
+
+	size_aligned -= base_aligned;
 
 	if (plane_config->size == 0)
 		return false;
 
-	obj = i915_gem_object_create_stolen_for_preallocated(dev, base, base,
-							     plane_config->size);
+	obj = i915_gem_object_create_stolen_for_preallocated(dev,
+							     base_aligned,
+							     base_aligned,
+							     size_aligned);
 	if (!obj)
 		return false;
 
@@ -6654,7 +6660,7 @@ i9xx_get_initial_plane_config(struct intel_crtc *crtc,
 	aligned_height = intel_fb_align_height(dev, fb->height,
 					       plane_config->tiling);
 
-	plane_config->size = PAGE_ALIGN(fb->pitches[0] * aligned_height);
+	plane_config->size = fb->pitches[0] * aligned_height;
 
 	DRM_DEBUG_KMS("pipe/plane %c/%d with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
 		      pipe_name(pipe), plane, fb->width, fb->height,
@@ -7694,7 +7700,7 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
 	aligned_height = intel_fb_align_height(dev, fb->height,
 					       plane_config->tiling);
 
-	plane_config->size = ALIGN(fb->pitches[0] * aligned_height, PAGE_SIZE);
+	plane_config->size = fb->pitches[0] * aligned_height;
 
 	DRM_DEBUG_KMS("pipe %c with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
 		      pipe_name(pipe), fb->width, fb->height,
@@ -7787,7 +7793,7 @@ ironlake_get_initial_plane_config(struct intel_crtc *crtc,
 	aligned_height = intel_fb_align_height(dev, fb->height,
 					       plane_config->tiling);
 
-	plane_config->size = PAGE_ALIGN(fb->pitches[0] * aligned_height);
+	plane_config->size = fb->pitches[0] * aligned_height;
 
 	DRM_DEBUG_KMS("pipe %c with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
 		      pipe_name(pipe), fb->width, fb->height,
-- 
2.1.4