drm/amdgpu: skip the VMID 0 flush for VRAM

Clear-on-release only runs on VRAM, which amdgpu_ttm_map_buffer() reaches
via its direct MC address without programming a GART window, yet the wipe
still forces a VMID 0 flush. On GFX11 (e.g. Navi33) that spurious SDMA
flush can wedge the engine; only flush when a GART window is actually used.

v2: Let amdgpu_ttm_map_buffer() return whether the VMID 0 flush is needed,
    and drive the clear and copy paths from that. (Christian)
v3: Make the vm_needs_flush output parameter mandatory instead of
    allowing NULL. (Christian)

Fixes: a68c7eaa7a ("drm/amdgpu: Enable clear page functionality")
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5413
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit a306e406e5)
Cc: stable@vger.kernel.org
This commit is contained in:
Arunpravin Paneer Selvam 2026-09-02 18:33:48 +05:30 • committed by Alex Deucher
commit 87ceb8cba7