Attachment 123521 Details for Bug 95198 – bandaid patch for SI

[patch] bandaid patch for SI

0001-radeonsi-workaround-for-tesselation-on-SI.patch (text/plain), 1.66 KB, created by Nicolai Hähnle on 2016-05-06 16:58:27 UTC

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Creator: Nicolai Hähnle

Created: 2016-05-06 16:58:27 UTC

Size: 1.66 KB

patch

obsolete

>From c64afadcffab6bb57f7e15cdb52046383d4b1a81 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <nicolai.haehnle@amd.com>
>Date: Fri, 6 May 2016 11:52:17 -0500
>Subject: [PATCH] radeonsi: workaround for tesselation on SI
>
>We request more than 32KB of LDS here, which SI doesn't have. Since LLVM
>recently started checking the size of LDS allocations, all shaders involved
>in tesselation fail to compile on SI.
>
>Note that the entire calculation here seems wrong: each input/output of each
>vertex actually occupies 16 bytes rather than just 4, so this will fail for
>large vertices on CI+ as well.
>
>A proper solution is clearly needed, but this patch should serve as a band-aid
>for SI in the meantime.
>---
> src/gallium/drivers/radeonsi/si_shader.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
>diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
>index 49c498d..c9d3a95 100644
>--- a/src/gallium/drivers/radeonsi/si_shader.c
>+++ b/src/gallium/drivers/radeonsi/si_shader.c
>@@ -4952,6 +4952,16 @@ static void declare_tess_lds(struct si_shader_context *ctx)
> 	unsigned patch_dw_size = vertex_data_dw_size*2 + patch_data_dw_size;
> 	unsigned lds_dwords = patch_dw_size;
> 
>+	if (ctx->screen->b.chip_class <= SI) {
>+		/* This is a horrible temporary workaround to make tesselation
>+		 * not be completely broken on SI now that LLVM checks that
>+		 * the declared LDS size fits into the device maximum of 32KB.
>+		 *
>+		 * The real long term solution requires off-chip tesselation.
>+		 */
>+		patch_dw_size = 8 * 1024;
>+	}
>+
> 	/* The actual size is computed outside of the shader to reduce
> 	 * the number of shader variants. */
> 	ctx->lds =
>-- 
>2.7.4
>

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Attachments on bug 95198: 123332 | 123504 | 123521 | 123530 | 123543

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