intel-gtt: adjust overhead entries in intel_gtt_stolen_entries

agp/intel_gtt.c and drm/i915/i915_dma.c don't calculate this the same
way: The intel-gtt code seems to use the actual gtt size, the drm
module just the mappable. Go with the logic from the drm module because
that's the more conservative choice.

But conserve the original code in intel_gtt_total_size for later use.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/char/agp/intel-gtt.c

@@ -537,76 +537,19 @@ static unsigned int intel_gtt_stolen_entries(void)
 	u8 rdct;
 	int local = 0;
 	static const int ddt[4] = { 0, 16, 32, 64 };
-	int size; /* reserved space (in kb) at the top of stolen memory */
 	unsigned int overhead_entries, stolen_entries;
 	unsigned int stolen_size = 0;
 
 	pci_read_config_word(intel_private.bridge_dev,
 			     I830_GMCH_CTRL, &gmch_ctrl);
 
-	if (IS_I965) {
-		u32 pgetbl_ctl;
-		pgetbl_ctl = readl(intel_private.registers+I810_PGETBL_CTL);
-
-		/* The 965 has a field telling us the size of the GTT,
-		 * which may be larger than what is necessary to map the
-		 * aperture.
-		 */
-		switch (pgetbl_ctl & I965_PGETBL_SIZE_MASK) {
-		case I965_PGETBL_SIZE_128KB:
-			size = 128;
-			break;
-		case I965_PGETBL_SIZE_256KB:
-			size = 256;
-			break;
-		case I965_PGETBL_SIZE_512KB:
-			size = 512;
-			break;
-		case I965_PGETBL_SIZE_1MB:
-			size = 1024;
-			break;
-		case I965_PGETBL_SIZE_2MB:
-			size = 2048;
-			break;
-		case I965_PGETBL_SIZE_1_5MB:
-			size = 1024 + 512;
-			break;
-		default:
-			dev_info(&intel_private.pcidev->dev,
-				 "unknown page table size, assuming 512KB\n");
-			size = 512;
-		}
-		size += 4; /* add in BIOS popup space */
-	} else if (IS_G33 && !IS_PINEVIEW) {
-	/* G33's GTT size defined in gmch_ctrl */
-		switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) {
-		case G33_PGETBL_SIZE_1M:
-			size = 1024;
-			break;
-		case G33_PGETBL_SIZE_2M:
-			size = 2048;
-			break;
-		default:
-			dev_info(&intel_private.bridge_dev->dev,
-				 "unknown page table size 0x%x, assuming 512KB\n",
-				(gmch_ctrl & G33_PGETBL_SIZE_MASK));
-			size = 512;
-		}
-		size += 4;
-	} else if (IS_G4X || IS_PINEVIEW) {
-		/* On 4 series hardware, GTT stolen is separate from graphics
-		 * stolen, ignore it in stolen gtt entries counting.  However,
-		 * 4KB of the stolen memory doesn't get mapped to the GTT.
-		 */
-		size = 4;
-	} else {
-		/* On previous hardware, the GTT size was just what was
-		 * required to map the aperture.
-		 */
-		size = agp_bridge->driver->fetch_size() + 4;
-	}
+	if (IS_G4X || IS_PINEVIEW)
+		overhead_entries = 0;
+	else
+		overhead_entries = intel_private.base.gtt_mappable_entries
+			/ 1024;
 
-	overhead_entries = size/4;
+	overhead_entries += 1; /* BIOS popup */
 
 	if (intel_private.bridge_dev->device == PCI_DEVICE_ID_INTEL_82830_HB ||
 	    intel_private.bridge_dev->device == PCI_DEVICE_ID_INTEL_82845G_HB) {
@@ -752,6 +695,78 @@ static unsigned int intel_gtt_stolen_entries(void)
 	return stolen_entries;
 }
 
+#if 0 /* extracted code in bad shape, needs some cleaning before use */
+static unsigned int intel_gtt_total_entries(void)
+{
+	int size;
+	u16 gmch_ctrl;
+
+	if (IS_I965) {
+		u32 pgetbl_ctl;
+		pgetbl_ctl = readl(intel_private.registers+I810_PGETBL_CTL);
+
+		/* The 965 has a field telling us the size of the GTT,
+		 * which may be larger than what is necessary to map the
+		 * aperture.
+		 */
+		switch (pgetbl_ctl & I965_PGETBL_SIZE_MASK) {
+		case I965_PGETBL_SIZE_128KB:
+			size = 128;
+			break;
+		case I965_PGETBL_SIZE_256KB:
+			size = 256;
+			break;
+		case I965_PGETBL_SIZE_512KB:
+			size = 512;
+			break;
+		case I965_PGETBL_SIZE_1MB:
+			size = 1024;
+			break;
+		case I965_PGETBL_SIZE_2MB:
+			size = 2048;
+			break;
+		case I965_PGETBL_SIZE_1_5MB:
+			size = 1024 + 512;
+			break;
+		default:
+			dev_info(&intel_private.pcidev->dev,
+				 "unknown page table size, assuming 512KB\n");
+			size = 512;
+		}
+		size += 4; /* add in BIOS popup space */
+	} else if (IS_G33 && !IS_PINEVIEW) {
+	/* G33's GTT size defined in gmch_ctrl */
+		switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) {
+		case G33_PGETBL_SIZE_1M:
+			size = 1024;
+			break;
+		case G33_PGETBL_SIZE_2M:
+			size = 2048;
+			break;
+		default:
+			dev_info(&intel_private.bridge_dev->dev,
+				 "unknown page table size 0x%x, assuming 512KB\n",
+				(gmch_ctrl & G33_PGETBL_SIZE_MASK));
+			size = 512;
+		}
+		size += 4;
+	} else if (IS_G4X || IS_PINEVIEW) {
+		/* On 4 series hardware, GTT stolen is separate from graphics
+		 * stolen, ignore it in stolen gtt entries counting.  However,
+		 * 4KB of the stolen memory doesn't get mapped to the GTT.
+		 */
+		size = 4;
+	} else {
+		/* On previous hardware, the GTT size was just what was
+		 * required to map the aperture.
+		 */
+		size = agp_bridge->driver->fetch_size() + 4;
+	}
+
+	return size/KB(4);
+}
+#endif
+
 static unsigned int intel_gtt_mappable_entries(void)
 {
 	unsigned int aperture_size;