[Intel-gfx] [PATCH] drm/i915: Discard large BIOS framebuffers causing display corruption.

[Ashish Arora]

From: Ashish Arora <ashisharora.linux at outlook.com>

On certain 4k panels, the BIOS framebuffer is larger than what panel
requires causing display corruption. Introduce a check for the same.

Signed-off-by: Ashish Arora <ashisharora.linux at outlook.com>
---
 drivers/gpu/drm/i915/display/intel_fbdev.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
index adc3a81be..f9952e1f8 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -193,6 +193,17 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	struct drm_i915_gem_object *obj;
 	int ret;
 
+	if (intel_fb &&
+	    (sizes->fb_width < intel_fb->base.width ||
+	     sizes->fb_height < intel_fb->base.height)) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "BIOS fb too large (%dx%d), we require (%dx%d),"
+			    " releasing it\n",
+			    intel_fb->base.width, intel_fb->base.height,
+			    sizes->fb_width, sizes->fb_height);
+		drm_framebuffer_put(&intel_fb->base);
+		intel_fb = ifbdev->fb = NULL;
+	}
 	if (intel_fb &&
 	    (sizes->fb_width > intel_fb->base.width ||
 	     sizes->fb_height > intel_fb->base.height)) {
-- 
2.25.1