drm/radeon/kms: fix agp mode setup on cards that use pcie bridges

Asics that use an AGP to PCIE bridge don't have the AGP_STATUS
register so just use whatever mode the host side setup.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: Jerome Glisse <glisse@freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_agp.c b/drivers/gpu/drm/radeon/radeon_agp.c
index f40dfb77f9b1..bd2f33e5c91a 100644
--- a/drivers/gpu/drm/radeon/radeon_agp.c
+++ b/drivers/gpu/drm/radeon/radeon_agp.c
@@ -156,7 +156,13 @@ int radeon_agp_init(struct radeon_device *rdev)
         }
 
         mode.mode = info.mode;
-        agp_status = (RREG32(RADEON_AGP_STATUS) | RADEON_AGPv3_MODE) & mode.mode;
+        /* chips with the agp to pcie bridge don't have the AGP_STATUS register
+         * Just use the whatever mode the host sets up.
+         */
+        if (rdev->family <= CHIP_RV350)
+                agp_status = (RREG32(RADEON_AGP_STATUS) | RADEON_AGPv3_MODE) & mode.mode;
+        else
+                agp_status = mode.mode;
         is_v3 = !!(agp_status & RADEON_AGPv3_MODE);
 
         if (is_v3) {