Attachment 123543 Details for Bug 95198 – bandaid patch for SI v2

[patch] bandaid patch for SI v2

0001-radeonsi-workaround-for-tesselation-on-SI.patch (text/plain), 1.78 KB, created by Nicolai Hähnle on 2016-05-07 22:17:22 UTC

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Creator: Nicolai Hähnle

Created: 2016-05-07 22:17:22 UTC

Size: 1.78 KB

patch

obsolete

>From b65cdfb84ddd5bac76af104e1634b64e340e22a7 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 declared LDS allocations, all shaders
>involved in tesselation fail to compile on SI.
>
>Note that the entire calculation here seems wrong, given how we calculate
>indices for generic attributes, so the number ends up wrong on CI+ as well.
>A proper solution is clearly needed, but this patch should serve as a band-aid
>for SI in the meantime.
>
>Also note that the real size of the LDS allocation in hardware is independent
>from what we tell LLVM, so this is really more of a "cosmetic" change.
>---
> 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 211db9f..8365f3d 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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