[Intel-gfx] [PATCH] drm/i915: kick any firmware framebuffers before claiming the gtt

[Singh, Satyeshwar]

Hi,
I just want to confirm something here. We have a situation where we draw a splash screen through our firmware's graphics component (UEFI GOP driver) onto its frame buffer which resides in stolen memory. When we transition from firmware to the kernel, we would like to ensure that the same splash screen seamlessly continues to be displayed so we remap the pages from stolen memory into GTT. If we have purged firmware framebuffers before claiming the gtt, then would we have not essentially lost the chance to remap those pages?
-Satyeshwar

-----Original Message-----
From: intel-gfx-bounces+satyeshwar.singh=intel.com at lists.freedesktop.org [mailto:intel-gfx-bounces+satyeshwar.singh=intel.com at lists.freedesktop.org] On Behalf Of Daniel Vetter
Sent: Tuesday, June 12, 2012 2:28 AM
To: Intel Graphics Development
Cc: Daniel Vetter; Ben Widawsky
Subject: [Intel-gfx] [PATCH] drm/i915: kick any firmware framebuffers before claiming the gtt

Especially vesafb likes to map everything as uc- (yikes), and if that mapping hangs around still while we try to map the gtt as wc the kernel will downgrade our request to uc-, resulting in abyssal performance.

Unfortunately we can't do this as early as readon does (i.e. as the first thing we do when initializing the hw) because our fb/mmio space region moves around on a per-gen basis. So I've had to move it below the gtt initialization, but that seems to work, too. The important thing is that we do this before we set up the gtt wc mapping.

Now an altogether different question is why people compile their kernels with vesafb enabled, but I guess making things just work isn't bad per se ...

v2:
- s/radeondrmfb/inteldrmfb/
- fix up error handling

v3: Kill #ifdef X86, this is Intel after all. Noticed by Ben Widawsky.

v4: Jani Nikula complained about the pointless bool primary initialization.

v5: Don't oops if we can't allocate, noticed by Chris Wilson.

Reported-and-tested-by: "Kilarski, Bernard R" <bernard.r.kilarski at intel.com>
Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_dma.c |   37 ++++++++++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 262a74d..2e37b92 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1401,6 +1401,27 @@ i915_mtrr_setup(struct drm_i915_private *dev_priv, unsigned long base,
 	}
 }
 
+static void i915_kick_out_firmware_fb(struct drm_i915_private 
+*dev_priv) {
+	struct apertures_struct *ap;
+	struct pci_dev *pdev = dev_priv->dev->pdev;
+	bool primary;
+
+	ap = alloc_apertures(1);
+
+	if (!ap)
+		return;
+
+	ap->ranges[0].base = dev_priv->dev->agp->base;
+	ap->ranges[0].size =
+		dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;
+
+	primary = pdev->resource[PCI_ROM_RESOURCE].flags & 
+IORESOURCE_ROM_SHADOW;
+
+	remove_conflicting_framebuffers(ap, "inteldrmfb", primary);
+	kfree(ap);
+}
+
 /**
  * i915_driver_load - setup chip and create an initial config
  * @dev: DRM device
@@ -1446,6 +1467,15 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		goto free_priv;
 	}
 
+	dev_priv->mm.gtt = intel_gtt_get();
+	if (!dev_priv->mm.gtt) {
+		DRM_ERROR("Failed to initialize GTT\n");
+		ret = -ENODEV;
+		goto put_bridge;
+	}
+
+	i915_kick_out_firmware_fb(dev_priv);
+
 	pci_set_master(dev->pdev);
 
 	/* overlay on gen2 is broken and can't address above 1G */ @@ -1471,13 +1501,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		goto put_bridge;
 	}
 
-	dev_priv->mm.gtt = intel_gtt_get();
-	if (!dev_priv->mm.gtt) {
-		DRM_ERROR("Failed to initialize GTT\n");
-		ret = -ENODEV;
-		goto out_rmmap;
-	}
-
 	aperture_size = dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;
 
 	dev_priv->mm.gtt_mapping =
--
1.7.10

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