[01/94] Revert "drm/i915: Fix detection of base of stolen memory"

From: Ben Hutchings
Date: Mon May 27 2013 - 23:59:27 EST


3.2.46-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

This reverts commit 53e587aa5ca81497d0ea6e340320ec5778d1f311.
Yves-Alexis Perez reported that it broke the driver on two machines
with GMA4500 and i965 chips. Only the backported version in 3.2.45
had this effect; the fix in mainline is fine.

Daniel Vetter stated that the fix is not needed in 3.2 anyway.

Reported-by: Yves-Alexis Perez <corsac@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_dma.c | 81 +++++++++++++++++++--------------------
drivers/gpu/drm/i915/i915_drv.h | 1 -
2 files changed, 40 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index c77fc67..ca67338 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1007,50 +1007,56 @@ intel_teardown_mchbar(struct drm_device *dev)
release_resource(&dev_priv->mch_res);
}

-static unsigned long i915_stolen_to_physical(struct drm_device *dev)
+#define PTE_ADDRESS_MASK 0xfffff000
+#define PTE_ADDRESS_MASK_HIGH 0x000000f0 /* i915+ */
+#define PTE_MAPPING_TYPE_UNCACHED (0 << 1)
+#define PTE_MAPPING_TYPE_DCACHE (1 << 1) /* i830 only */
+#define PTE_MAPPING_TYPE_CACHED (3 << 1)
+#define PTE_MAPPING_TYPE_MASK (3 << 1)
+#define PTE_VALID (1 << 0)
+
+/**
+ * i915_stolen_to_phys - take an offset into stolen memory and turn it into
+ * a physical one
+ * @dev: drm device
+ * @offset: address to translate
+ *
+ * Some chip functions require allocations from stolen space and need the
+ * physical address of the memory in question.
+ */
+static unsigned long i915_stolen_to_phys(struct drm_device *dev, u32 offset)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct pci_dev *pdev = dev_priv->bridge_dev;
u32 base;

+#if 0
/* On the machines I have tested the Graphics Base of Stolen Memory
- * is unreliable, so on those compute the base by subtracting the
- * stolen memory from the Top of Low Usable DRAM which is where the
- * BIOS places the graphics stolen memory.
- *
- * On gen2, the layout is slightly different with the Graphics Segment
- * immediately following Top of Memory (or Top of Usable DRAM). Note
- * it appears that TOUD is only reported by 865g, so we just use the
- * top of memory as determined by the e820 probe.
- *
- * XXX gen2 requires an unavailable symbol and 945gm fails with
- * its value of TOLUD.
+ * is unreliable, so compute the base by subtracting the stolen memory
+ * from the Top of Low Usable DRAM which is where the BIOS places
+ * the graphics stolen memory.
*/
- base = 0;
- if (INTEL_INFO(dev)->gen >= 6) {
- /* Read Base Data of Stolen Memory Register (BDSM) directly.
- * Note that there is also a MCHBAR miror at 0x1080c0 or
- * we could use device 2:0x5c instead.
- */
- pci_read_config_dword(pdev, 0xB0, &base);
- base &= ~4095; /* lower bits used for locking register */
- } else if (INTEL_INFO(dev)->gen > 3 || IS_G33(dev)) {
- /* Read Graphics Base of Stolen Memory directly */
+ if (INTEL_INFO(dev)->gen > 3 || IS_G33(dev)) {
+ /* top 32bits are reserved = 0 */
pci_read_config_dword(pdev, 0xA4, &base);
-#if 0
- } else if (IS_GEN3(dev)) {
+ } else {
+ /* XXX presume 8xx is the same as i915 */
+ pci_bus_read_config_dword(pdev->bus, 2, 0x5C, &base);
+ }
+#else
+ if (INTEL_INFO(dev)->gen > 3 || IS_G33(dev)) {
+ u16 val;
+ pci_read_config_word(pdev, 0xb0, &val);
+ base = val >> 4 << 20;
+ } else {
u8 val;
- /* Stolen is immediately below Top of Low Usable DRAM */
pci_read_config_byte(pdev, 0x9c, &val);
base = val >> 3 << 27;
- base -= dev_priv->mm.gtt->stolen_size;
- } else {
- /* Stolen is immediately above Top of Memory */
- base = max_low_pfn_mapped << PAGE_SHIFT;
-#endif
}
+ base -= dev_priv->mm.gtt->stolen_size;
+#endif

- return base;
+ return base + offset;
}

static void i915_warn_stolen(struct drm_device *dev)
@@ -1075,7 +1081,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
if (!compressed_fb)
goto err;

- cfb_base = dev_priv->mm.stolen_base + compressed_fb->start;
+ cfb_base = i915_stolen_to_phys(dev, compressed_fb->start);
if (!cfb_base)
goto err_fb;

@@ -1088,7 +1094,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
if (!compressed_llb)
goto err_fb;

- ll_base = dev_priv->mm.stolen_base + compressed_llb->start;
+ ll_base = i915_stolen_to_phys(dev, compressed_llb->start);
if (!ll_base)
goto err_llb;
}
@@ -1107,7 +1113,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
}

DRM_DEBUG_KMS("FBC base 0x%08lx, ll base 0x%08lx, size %dM\n",
- (long)cfb_base, (long)ll_base, size >> 20);
+ cfb_base, ll_base, size >> 20);
return;

err_llb:
@@ -1181,13 +1187,6 @@ static int i915_load_gem_init(struct drm_device *dev)
gtt_size = dev_priv->mm.gtt->gtt_total_entries << PAGE_SHIFT;
mappable_size = dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;

- dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
- if (dev_priv->mm.stolen_base == 0)
- return 0;
-
- DRM_DEBUG_KMS("found %d bytes of stolen memory at %08lx\n",
- dev_priv->mm.gtt->stolen_size, dev_priv->mm.stolen_base);
-
/* Basic memrange allocator for stolen space */
drm_mm_init(&dev_priv->mm.stolen, 0, prealloc_size);

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 20cd295..144d37c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -581,7 +581,6 @@ typedef struct drm_i915_private {
unsigned long gtt_start;
unsigned long gtt_mappable_end;
unsigned long gtt_end;
- unsigned long stolen_base; /* limited to low memory (32-bit) */

struct io_mapping *gtt_mapping;
int gtt_mtrr;

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