agp: use scratch page on memory remove and at GATT creation V4

Convert most AGP chipset to use scratch page as default entries.
This help avoiding GPU querying 0 address and trigger computer
fault. With KMS and memory manager we bind/unbind AGP memory
constantly and it seems that some GPU are still doing AGP
traffic even after GPU report being idle with the memory segment.

Tested (radeon GPU KMS + Xorg + compiz + glxgears + quake3) on :
- SIS 1039:0001 & 1039:0003
- Intel 865 8086:2571

Compile tested for other bridges

V2 enable scratch page on uninorth
V3 fix unbound check in uninorth insert memory (Michel Dänzer)
V4 rebase on top of drm-next branch with the lastest intel AGP
   changeset (stable should use version V3 of the patch)

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index 3b2ecbe86ebe..dc30e2243494 100644
--- a/drivers/char/agp/ati-agp.c
+++ b/drivers/char/agp/ati-agp.c
@@ -341,6 +341,7 @@ static int ati_create_gatt_table(struct agp_bridge_data *bridge)
 {
         struct aper_size_info_lvl2 *value;
         struct ati_page_map page_dir;
+        unsigned long __iomem *cur_gatt;
         unsigned long addr;
         int retval;
         u32 temp;
@@ -395,6 +396,12 @@ static int ati_create_gatt_table(struct agp_bridge_data *bridge)
                 readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));        /* PCI Posting. */
         }
 
+        for (i = 0; i < value->num_entries; i++) {
+                addr = (i * PAGE_SIZE) + agp_bridge->gart_bus_addr;
+                cur_gatt = GET_GATT(addr);
+                writel(agp_bridge->scratch_page, cur_gatt+GET_GATT_OFF(addr));
+        }
+
         return 0;
 }
 
@@ -415,6 +422,7 @@ static const struct agp_bridge_driver ati_generic_bridge = {
         .aperture_sizes         = ati_generic_sizes,
         .size_type              = LVL2_APER_SIZE,
         .num_aperture_sizes     = 7,
+        .needs_scratch_page     = true,
         .configure              = ati_configure,
         .fetch_size             = ati_fetch_size,
         .cleanup                = ati_cleanup,