[PATCH] radeon drm: fix agp aperture map offset

This finally fixes the radeon memory mapping bug that was incorrectly
fixed by the previous patch.  This time, we use the actual vram size as
the size to calculate how far to move the AGP aperture from the
framebuffer in card's memory space.

If there are still issues with this patch, they are due to bugs in the X
driver that I'm working on fixing too.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mark M. Hoffman <mhoffman@lightlink.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/char/drm/radeon_cp.c

@@ -1312,6 +1312,8 @@ static void radeon_set_pcigart(drm_radeon_private_t * dev_priv, int on)
 static int radeon_do_init_cp(drm_device_t * dev, drm_radeon_init_t * init)
 {
 	drm_radeon_private_t *dev_priv = dev->dev_private;;
+	unsigned int mem_size;
+
 	DRM_DEBUG("\n");
 
 	dev_priv->is_pci = init->is_pci;
@@ -1521,8 +1523,11 @@ static int radeon_do_init_cp(drm_device_t * dev, drm_radeon_init_t * init)
 					  + dev_priv->fb_location) >> 10));
 
 	dev_priv->gart_size = init->gart_size;
-	dev_priv->gart_vm_start = dev_priv->fb_location
-	    + RADEON_READ(RADEON_CONFIG_APER_SIZE) * 2;
+
+	mem_size = RADEON_READ(RADEON_CONFIG_MEMSIZE);
+	if (mem_size == 0)
+		mem_size = 0x800000;
+	dev_priv->gart_vm_start = dev_priv->fb_location + mem_size;
 
 #if __OS_HAS_AGP
 	if (!dev_priv->is_pci)

drivers/char/drm/radeon_drv.h

@@ -379,6 +379,7 @@ extern int r300_do_cp_cmdbuf(drm_device_t * dev, DRMFILE filp,
 #	define RADEON_PLL_WR_EN			(1 << 7)
 #define RADEON_CLOCK_CNTL_INDEX		0x0008
 #define RADEON_CONFIG_APER_SIZE		0x0108
+#define RADEON_CONFIG_MEMSIZE		0x00f8
 #define RADEON_CRTC_OFFSET		0x0224
 #define RADEON_CRTC_OFFSET_CNTL		0x0228
 #	define RADEON_CRTC_TILE_EN		(1 << 15)