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, 2 insertions, 0 deletions

diff --git a/drivers/char/agp/via-agp.c b/drivers/char/agp/via-agp.c
index d3bd243867fc..df67e80019d2 100644
--- a/drivers/char/agp/via-agp.c
+++ b/drivers/char/agp/via-agp.c
@@ -175,6 +175,7 @@ static const struct agp_bridge_driver via_agp3_driver = {
         .aperture_sizes         = agp3_generic_sizes,
         .size_type              = U8_APER_SIZE,
         .num_aperture_sizes     = 10,
+        .needs_scratch_page     = true,
         .configure              = via_configure_agp3,
         .fetch_size             = via_fetch_size_agp3,
         .cleanup                = via_cleanup_agp3,
@@ -201,6 +202,7 @@ static const struct agp_bridge_driver via_driver = {
         .aperture_sizes         = via_generic_sizes,
         .size_type              = U8_APER_SIZE,
         .num_aperture_sizes     = 9,
+        .needs_scratch_page     = true,
         .configure              = via_configure,
         .fetch_size             = via_fetch_size,
         .cleanup                = via_cleanup,