Patch "drm/amdgpu: refuse to reserve io mem for split VRAM buffers" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

drm/amdgpu: refuse to reserve io mem for split VRAM buffers

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-amdgpu-refuse-to-reserve-io-mem-for-split-vram-buffers.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Nicolai H�hnle <[email protected]>
Date: Thu, 16 Feb 2017 23:49:12 +0100
Subject: drm/amdgpu: refuse to reserve io mem for split VRAM buffers

From: Nicolai H�hnle <[email protected]>

[ Upstream commit 4694335dad7357e9b3d7822ab13049014d74d8b0 ]

When the fast blit path fails while attempting to move a buffer from RAM to VRAM, we fall back to a CPU-based memcpy that cannot handle split VRAM buffers. Instead of crashing, simply fail the buffer move.

Ideally, we would teach TTM about split buffers so that the fallback still works in this case, but that is quite involved. So for now, apply the simplest possible fix.

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -491,6 +491,9 @@ static int amdgpu_ttm_io_mem_reserve(str
 	case TTM_PL_TT:
 		break;
 	case TTM_PL_VRAM:
+		if (mem->start == AMDGPU_BO_INVALID_OFFSET)
+			return -EINVAL;
+
 		mem->bus.offset = mem->start << PAGE_SHIFT;
 		/* check if it's visible */
 		if ((mem->bus.offset + mem->bus.size) > adev->mc.visible_vram_size)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-amdgpu-refuse-to-reserve-io-mem-for-split-vram-buffers.patch