Commit 7fa28e14 authored by Chris Wilson's avatar Chris Wilson

drm/i915: Write GPU relocs harder with gen3

Under moderate amounts of GPU stress, we can observe on Bearlake and
Pineview (later gen3 models) that we execute the following batch buffer
before the write into the batch is coherent. Adding extra (tested with
upto 32x) MI_FLUSH to either the invalidation, flush or both phases does
not solve the incoherency issue with the relocations, but emitting the
MI_STORE_DWORD_IMM twice does. So be it.

Fixes: 7dd4f672 ("drm/i915: Async GPU relocation processing")
Testcase: igt/gem_tiled_fence_blits # blb/pnv
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181119154153.15327-1-chris@chris-wilson.co.uk
parent fb6f0b64
......@@ -1268,7 +1268,7 @@ relocate_entry(struct i915_vma *vma,
else if (gen >= 4)
len = 4;
else
len = 3;
len = 6;
batch = reloc_gpu(eb, vma, len);
if (IS_ERR(batch))
......@@ -1309,6 +1309,11 @@ relocate_entry(struct i915_vma *vma,
*batch++ = MI_STORE_DWORD_IMM | MI_MEM_VIRTUAL;
*batch++ = addr;
*batch++ = target_offset;
/* And again for good measure (blb/pnv) */
*batch++ = MI_STORE_DWORD_IMM | MI_MEM_VIRTUAL;
*batch++ = addr;
*batch++ = target_offset;
}
goto out;
......
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