X-Git-Url: http://git.agner.ch/gitweb/?p=linux-drm-fsl-dcu.git;a=blobdiff_plain;f=drivers%2Fchar%2Fagp%2Fgeneric.c;h=883a36a278332ee6912ab9f19be236e3548ec5aa;hp=cc5ea347a8a7899a9e3228289697a2cd88378839;hb=f0eef25339f92f7cd4aeea23d9ae97987a5a1e82;hpb=0a1340c185734a57fbf4775927966ad4a1347b02

diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index cc5ea347a8a7..883a36a27833 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -419,6 +419,31 @@ static void agp_v2_parse_one(u32 *requested_mode, u32 *bridge_agpstat, u32 *vga_
 		*requested_mode &= ~AGP2_RESERVED_MASK;
 	}
 
+	/*
+	 * Some dumb bridges are programmed to disobey the AGP2 spec.
+	 * This is likely a BIOS misprogramming rather than poweron default, or
+	 * it would be a lot more common.
+	 * https://bugs.freedesktop.org/show_bug.cgi?id=8816
+	 * AGPv2 spec 6.1.9 states:
+	 *   The RATE field indicates the data transfer rates supported by this
+	 *   device. A.G.P. devices must report all that apply.
+	 * Fix them up as best we can.
+	 */
+	switch (*bridge_agpstat & 7) {
+	case 4:
+		*bridge_agpstat |= (AGPSTAT2_2X | AGPSTAT2_1X);
+		printk(KERN_INFO PFX "BIOS bug. AGP bridge claims to only support x4 rate"
+			"Fixing up support for x2 & x1\n");
+		break;
+	case 2:
+		*bridge_agpstat |= AGPSTAT2_1X;
+		printk(KERN_INFO PFX "BIOS bug. AGP bridge claims to only support x2 rate"
+			"Fixing up support for x1\n");
+		break;
+	default:
+		break;
+	}
+
 	/* Check the speed bits make sense. Only one should be set. */
 	tmp = *requested_mode & 7;
 	switch (tmp) {
@@ -568,25 +593,37 @@ static void agp_v3_parse_one(u32 *requested_mode, u32 *bridge_agpstat, u32 *vga_
 		*bridge_agpstat &= ~(AGPSTAT3_4X | AGPSTAT3_RSVD);
 		goto done;
 
+	} else if (*requested_mode & AGPSTAT3_4X) {
+		*bridge_agpstat &= ~(AGPSTAT3_8X | AGPSTAT3_RSVD);
+		*bridge_agpstat |= AGPSTAT3_4X;
+		goto done;
+
 	} else {
 
 		/*
-		 * If we didn't specify AGPx8, we can only do x4.
-		 * If the hardware can't do x4, we're up shit creek, and never
-		 *  should have got this far.
+		 * If we didn't specify an AGP mode, we see if both
+		 * the graphics card, and the bridge can do x8, and use if so.
+		 * If not, we fall back to x4 mode.
 		 */
-		*bridge_agpstat &= ~(AGPSTAT3_8X | AGPSTAT3_RSVD);
-		if ((*bridge_agpstat & AGPSTAT3_4X) && (*vga_agpstat & AGPSTAT3_4X))
-			*bridge_agpstat |= AGPSTAT3_4X;
-		else {
-			printk(KERN_INFO PFX "Badness. Don't know which AGP mode to set. "
-							"[bridge_agpstat:%x vga_agpstat:%x fell back to:- bridge_agpstat:%x vga_agpstat:%x]\n",
-							origbridge, origvga, *bridge_agpstat, *vga_agpstat);
-			if (!(*bridge_agpstat & AGPSTAT3_4X))
-				printk(KERN_INFO PFX "Bridge couldn't do AGP x4.\n");
-			if (!(*vga_agpstat & AGPSTAT3_4X))
-				printk(KERN_INFO PFX "Graphic card couldn't do AGP x4.\n");
-			return;
+		if ((*bridge_agpstat & AGPSTAT3_8X) && (*vga_agpstat & AGPSTAT3_8X)) {
+			printk(KERN_INFO PFX "No AGP mode specified. Setting to highest mode "
+				"supported by bridge & card (x8).\n");
+			*bridge_agpstat &= ~(AGPSTAT3_4X | AGPSTAT3_RSVD);
+			*vga_agpstat &= ~(AGPSTAT3_4X | AGPSTAT3_RSVD);
+		} else {
+			printk(KERN_INFO PFX "Fell back to AGPx4 mode because");
+			if (!(*bridge_agpstat & AGPSTAT3_8X)) {
+				printk(KERN_INFO PFX "bridge couldn't do x8. bridge_agpstat:%x (orig=%x)\n",
+					*bridge_agpstat, origbridge);
+				*bridge_agpstat &= ~(AGPSTAT3_8X | AGPSTAT3_RSVD);
+				*bridge_agpstat |= AGPSTAT3_4X;
+			}
+			if (!(*vga_agpstat & AGPSTAT3_8X)) {
+				printk(KERN_INFO PFX "graphics card couldn't do x8. vga_agpstat:%x (orig=%x)\n",
+					*vga_agpstat, origvga);
+				*vga_agpstat &= ~(AGPSTAT3_8X | AGPSTAT3_RSVD);
+				*vga_agpstat |= AGPSTAT3_4X;
+			}
 		}
 	}
 
@@ -1042,7 +1079,7 @@ void *agp_generic_alloc_page(struct agp_bridge_data *bridge)
 {
 	struct page * page;
 
-	page = alloc_page(GFP_KERNEL);
+	page = alloc_page(GFP_KERNEL | GFP_DMA32);
 	if (page == NULL)
 		return NULL;