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[0556/1094] drm/i915: Discard BIOS framebuffers too small to accommodate chosen mode

Message ID 1413889294-31328-557-git-send-email-dheerajx.s.jamwal@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:52 a.m. UTC 
From: Chris Wilson <chris@chris-wilson.co.uk>

If the inherited BIOS framebuffer is smaller than the mode selected for
fbdev, then if we continue to use it then we cause display corruption as
we do not setup the panel fitter to upscale.

Regression from commit d978ef14456a38034f6c0e94a794129501f89200
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Mar 7 08:57:51 2014 -0800

    drm/i915: Wrap the preallocated BIOS framebuffer and preserve for KMS fbcon v12

v2: Add a debug message to track the discard of the BIOS fb.
v3: Ville pointed out the difference between ref/unref

Reported-by: Knut Petersen <Knut_Petersen@t-online.de>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77767
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit edd586fe705e819bc711b5ed7194a0b6f9f1a7e1)

Signed-off-by: Dheeraj Jamwal <dheerajx.s.jamwal@intel.com>
---
 drivers/gpu/drm/i915/intel_fbdev.c |   10 ++++++++++
 1 file changed, 10 insertions(+)
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Patch

diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index b4d44e6..fce4a0d 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -132,6 +132,16 @@  static int intelfb_create(struct drm_fb_helper *helper,
 
 	mutex_lock(&dev->struct_mutex);
 
+	if (intel_fb &&
+	    (sizes->fb_width > intel_fb->base.width ||
+	     sizes->fb_height > intel_fb->base.height)) {
+		DRM_DEBUG_KMS("BIOS fb too small (%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_unreference(&intel_fb->base);
+		intel_fb = ifbdev->fb = NULL;
+	}
 	if (!intel_fb || WARN_ON(!intel_fb->obj)) {
 		DRM_DEBUG_KMS("no BIOS fb, allocating a new one\n");
 		ret = intelfb_alloc(helper, sizes);