drm/radeon: fix problem with changing active VRAM size. (v2)

So we used to use lpfn directly to restrict VRAM when we couldn't
access the unmappable area, however this was removed in
93225b0d7bc030f4a93165347a65893685822d70 as it also restricted
the gtt placements. However it was only later noticed that this
broke on some hw.

This removes the active_vram_size, and just explicitly sets it
when it changes, TTM/drm_mm will always use the real_vram_size,
and the active vram size will change the TTM size used for lpfn
setting.

We should re-work the fpfn/lpfn to per-placement at some point
I suspect, but that is too late for this kernel.

Hopefully this addresses:
https://bugs.freedesktop.org/show_bug.cgi?id=35254

v2: fix reported useful VRAM size to userspace to be correct.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index e5b2cf10cbf..8389b4c63d1 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -589,6 +589,20 @@ void radeon_ttm_fini(struct radeon_device *rdev)
 	DRM_INFO("radeon: ttm finalized\n");
 }
 
+/* this should only be called at bootup or when userspace
+ * isn't running */
+void radeon_ttm_set_active_vram_size(struct radeon_device *rdev, u64 size)
+{
+	struct ttm_mem_type_manager *man;
+
+	if (!rdev->mman.initialized)
+		return;
+
+	man = &rdev->mman.bdev.man[TTM_PL_VRAM];
+	/* this just adjusts TTM size idea, which sets lpfn to the correct value */
+	man->size = size >> PAGE_SHIFT;
+}
+
 static struct vm_operations_struct radeon_ttm_vm_ops;
 static const struct vm_operations_struct *ttm_vm_ops = NULL;