This is one part in a few fixes needed to make FBC work with limited
stolen memory and large resolution displays. It is not the full
solution, but one (easy) step.
The patch is straight-forward, it attempts to check there will be room
for FBC before trying to "reclaim"
This modifies behavior originally introduced:
commit 0ffb0ff283cca16f72caf29c44496d83b0c291fb
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Thu Nov 15 11:32:27 2012 +0000
drm/i915: Allocate fbcon from stolen memory
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_fbdev.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 27975c3..ca83af8 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -57,6 +57,36 @@ static struct fb_ops intelfb_ops = {
.fb_debug_leave = drm_fb_helper_debug_leave,
};
+static bool intelfb_use_stolen(struct drm_device *dev, struct drm_mm *mm,
+ int size)
+{
+ struct drm_mm_node *entry;
+ unsigned long adj_start;
+ unsigned long adj_end;
+
+ if (!drm_mm_initialized(mm))
+ return false;
+
+ if (!HAS_FBC(dev))
+ return true;
+
+ /* It is more desirable to use FBC (if enabled) than to allocate the
+ * framebuffer from stolen. We can cheat this by rounding up the size by
+ * 2 (and hope to get lucky with alignment). The other options are more
+ * invasive, and arguably not any more effective.
+ */
+ size *= 2;
+ __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
+ DRM_MM_SEARCH_DEFAULT) {
+ if (adj_end - adj_start < size)
+ continue;
+
+ if (adj_end >= adj_start + size)
+ return true;
+ }
+
+ return false;
+}
static int intelfb_alloc(struct drm_fb_helper *helper,
struct drm_fb_helper_surface_size *sizes)
{
@@ -64,8 +94,9 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
container_of(helper, struct intel_fbdev, helper);
struct drm_framebuffer *fb;
struct drm_device *dev = helper->dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_mode_fb_cmd2 mode_cmd = {};
- struct drm_i915_gem_object *obj;
+ struct drm_i915_gem_object *obj = NULL;
int size, ret;
/* we don't do packed 24bpp */
@@ -82,7 +113,9 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
size = mode_cmd.pitches[0] * mode_cmd.height;
size = ALIGN(size, PAGE_SIZE);
- obj = i915_gem_object_create_stolen(dev, size);
+
+ if (intelfb_use_stolen(dev, &dev_priv->mm.stolen, size))
+ obj = i915_gem_object_create_stolen(dev, size);
if (obj == NULL)
obj = i915_gem_alloc_object(dev, size);
if (!obj) {
--
2.0.0
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