Mesa (mesa_7_6_branch): r300: Workaround problem on R500 with very large fragment programs

[Nicolai Hähnle]

Module: Mesa
Branch: mesa_7_6_branch
Commit: bbe384c86afeaf5995cddd286a76e1fd789e18f1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=bbe384c86afeaf5995cddd286a76e1fd789e18f1

Author: Nicolai Hähnle <nhaehnle at gmail.com>
Date:   Sat Oct  3 01:26:38 2009 +0200

r300: Workaround problem on R500 with very large fragment programs

The non-KMS interface is to blame here. In theory, a proper fix
could be produced that works for the KMS interface only, but it
require cleaning a lot of mess. Easier to just do it right in r300g.

Signed-off-by: Nicolai Hähnle <nhaehnle at gmail.com>

---

 docs/relnotes-7.6.1.html                         |    1 +
 src/mesa/drivers/dri/r300/r300_context.c         |   20 +++++++++++++++-----
 src/mesa/drivers/dri/r300/r300_fragprog_common.c |   13 +++++++++++++
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/docs/relnotes-7.6.1.html b/docs/relnotes-7.6.1.html
index a475845..d69af7a 100644
--- a/docs/relnotes-7.6.1.html
+++ b/docs/relnotes-7.6.1.html
@@ -41,6 +41,7 @@ tbd
 <li>glXQueryContext(GLX_RENDER_TYPE) returned wrong values (bug 24211)
 <li>GLSL sqrt(0) returned unpredictable results
 <li>Fixed default texture binding bug when a bound texture was deleted.
+<li>r300: Work around an issue with very large fragment programs on R500.
 </ul>
 
 </body>
diff --git a/src/mesa/drivers/dri/r300/r300_context.c b/src/mesa/drivers/dri/r300/r300_context.c
index 2ea1b82..9df3897 100644
--- a/src/mesa/drivers/dri/r300/r300_context.c
+++ b/src/mesa/drivers/dri/r300/r300_context.c
@@ -374,11 +374,21 @@ static void r300InitConstValues(GLcontext *ctx, radeonScreenPtr screen)
 	if (screen->chip_family >= CHIP_FAMILY_RV515) {
 		ctx->Const.FragmentProgram.MaxNativeTemps = R500_PFS_NUM_TEMP_REGS;
 		ctx->Const.FragmentProgram.MaxNativeAttribs = 11;	/* copy i915... */
-		ctx->Const.FragmentProgram.MaxNativeParameters = R500_PFS_NUM_CONST_REGS;
-		ctx->Const.FragmentProgram.MaxNativeAluInstructions = R500_PFS_MAX_INST;
-		ctx->Const.FragmentProgram.MaxNativeTexInstructions = R500_PFS_MAX_INST;
-		ctx->Const.FragmentProgram.MaxNativeInstructions = R500_PFS_MAX_INST;
-		ctx->Const.FragmentProgram.MaxNativeTexIndirections = R500_PFS_MAX_INST;
+
+		/* The hardware limits are higher than this,
+		 * but the non-KMS DRM interface artificially limits us
+		 * to this many instructions.
+		 *
+		 * We could of course work around it in the KMS path,
+		 * but it would be a mess, so it seems wiser
+		 * to leave it as is. Going forward, the Gallium driver
+		 * will not be subject to these limitations.
+		 */
+		ctx->Const.FragmentProgram.MaxNativeParameters = 255;
+		ctx->Const.FragmentProgram.MaxNativeAluInstructions = 255;
+		ctx->Const.FragmentProgram.MaxNativeTexInstructions = 255;
+		ctx->Const.FragmentProgram.MaxNativeInstructions = 255;
+		ctx->Const.FragmentProgram.MaxNativeTexIndirections = 255;
 		ctx->Const.FragmentProgram.MaxNativeAddressRegs = 0;
 	} else {
 		ctx->Const.FragmentProgram.MaxNativeTemps = R300_PFS_NUM_TEMP_REGS;
diff --git a/src/mesa/drivers/dri/r300/r300_fragprog_common.c b/src/mesa/drivers/dri/r300/r300_fragprog_common.c
index 0bdc90b..70c9252 100644
--- a/src/mesa/drivers/dri/r300/r300_fragprog_common.c
+++ b/src/mesa/drivers/dri/r300/r300_fragprog_common.c
@@ -239,6 +239,19 @@ static void translate_fragment_program(GLcontext *ctx, struct r300_fragment_prog
 	rewriteFog(&compiler, fp);
 
 	r3xx_compile_fragment_program(&compiler);
+
+	if (compiler.is_r500) {
+		/* We need to support the non-KMS DRM interface, which
+		 * artificially limits the number of instructions and
+		 * constants which are available to us.
+		 *
+		 * See also the comment in r300_context.c where we
+		 * set the MAX_NATIVE_xxx values.
+		 */
+		if (fp->code.code.r500.inst_end >= 255 || fp->code.constants.Count > 255)
+			rc_error(&compiler.Base, "Program is too big (upgrade to r300g to avoid this limitation).\n");
+	}
+
 	fp->error = compiler.Base.Error;
 
 	fp->InputsRead = compiler.Base.Program.InputsRead;