On Mon Feb 2 10:47:51 2026 +0100, Arnd Bergmann wrote:
> The deeply nested loop in rkvdec_init_v4l2_vp9_count_tbl() needs a lot
> of registers, so when the clang register allocator runs out, it ends up
> spilling countless temporaries to the stack:
>
> drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c:966:12: error: stack
> frame size (1472) exceeds limit (1280) in 'rkvdec_vp9_start'
> [-Werror,-Wframe-larger-than]
>
> Marking this function as noinline_for_stack keeps it out of
> rkvdec_vp9_start(), giving the compiler more room for optimization.
>
> The resulting code is good enough that both the total stack usage
> and the loop get enough better to stay under the warning limit,
> though it's still slow, and would need a larger rework if this
> function ends up being called in a fast path.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> Reviewed-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Patch committed.
Thanks,
Mauro Carvalho Chehab
drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
b/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
index e4cdd2122873..2751f5396ee8 100644
--- a/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
+++ b/drivers/media/platform/rockchip/rkvdec/rkvdec-vp9.c
@@ -893,7 +893,8 @@ out_update_last:
update_ctx_last_info(vp9_ctx);
}
-static void rkvdec_init_v4l2_vp9_count_tbl(struct rkvdec_ctx *ctx)
+static noinline_for_stack void
+rkvdec_init_v4l2_vp9_count_tbl(struct rkvdec_ctx *ctx)
{
struct rkvdec_vp9_ctx *vp9_ctx = ctx->priv;
struct rkvdec_vp9_intra_frame_symbol_counts *intra_cnts =
vp9_ctx->count_tbl.cpu;
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