[PATCH v2] mesa.inc: potentially enable texture float for gallium

[Trevor Woerner <twoerner@gmail.com>]

Following the lead from Fedora (as suggested by Rob Clark) always enable
--enable-texture-float for all gallium drivers, but then modify the code to
not enable it where the implementation isn't backed by hardware.

Somewhere along the path from OpenGL ES 2.0 to OpenGL ES 3.0 are some
algorithms that are encumbered by patents. These algorithms are enabled
with mesa's --enable-texture-float configure flag. However, if hardware
acceleration is being used and the hardware supports --enable-texture-float,
it means the hardware vendor has paid for the patents.

Note that with this solution, non-hardware gallium drivers (e.g. swrast) can't
--enable-texture-float, which might cause issues with some piglit tests.

This solution was disgussed and agreed-to on the mailing list:
http://lists.openembedded.org/pipermail/openembedded-core/2017-May/137233.html

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
 .../mesa/files/0002-hardware-gloat.patch           | 50 ++++++++++++++++++++++
 meta/recipes-graphics/mesa/mesa.inc                |  2 +-
 meta/recipes-graphics/mesa/mesa_17.1.1.bb          |  1 +
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 meta/recipes-graphics/mesa/files/0002-hardware-gloat.patch

diff --git a/meta/recipes-graphics/mesa/files/0002-hardware-gloat.patch b/meta/recipes-graphics/mesa/files/0002-hardware-gloat.patch
new file mode 100644
index 0000000000..9af9ae3b4b
--- /dev/null
+++ b/meta/recipes-graphics/mesa/files/0002-hardware-gloat.patch
@@ -0,0 +1,50 @@
+From 00bcd599310dc7fce4fe336ffd85902429051a0c Mon Sep 17 00:00:00 2001
+From: Igor Gnatenko <i.gnatenko.brain@gmail.com>
+Date: Sun, 20 Mar 2016 13:27:04 +0100
+Subject: [PATCH 2/4] hardware gloat
+
+Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
+---
+ src/gallium/drivers/llvmpipe/lp_screen.c | 7 +++++++
+ src/gallium/drivers/softpipe/sp_screen.c | 7 +++++++
+ 2 files changed, 14 insertions(+)
+
+diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
+index 4f61de8..3b0ec77 100644
+--- a/src/gallium/drivers/llvmpipe/lp_screen.c
++++ b/src/gallium/drivers/llvmpipe/lp_screen.c
+@@ -411,6 +411,13 @@ llvmpipe_is_format_supported( struct pipe_screen *_screen,
+    if (!format_desc)
+       return FALSE;
+ 
++   if ((bind & PIPE_BIND_RENDER_TARGET) &&
++       format != PIPE_FORMAT_R9G9B9E5_FLOAT &&
++       format != PIPE_FORMAT_R11G11B10_FLOAT &&
++       util_format_is_float(format)) {
++      return FALSE;
++   }
++
+    assert(target == PIPE_BUFFER ||
+           target == PIPE_TEXTURE_1D ||
+           target == PIPE_TEXTURE_1D_ARRAY ||
+diff --git a/src/gallium/drivers/softpipe/sp_screen.c b/src/gallium/drivers/softpipe/sp_screen.c
+index 031602b..c279120 100644
+--- a/src/gallium/drivers/softpipe/sp_screen.c
++++ b/src/gallium/drivers/softpipe/sp_screen.c
+@@ -358,6 +358,13 @@ softpipe_is_format_supported( struct pipe_screen *screen,
+    if (!format_desc)
+       return FALSE;
+ 
++   if ((bind & PIPE_BIND_RENDER_TARGET) &&
++       format != PIPE_FORMAT_R9G9B9E5_FLOAT &&
++       format != PIPE_FORMAT_R11G11B10_FLOAT &&
++       util_format_is_float(format)) {
++      return FALSE;
++   }
++
+    if (sample_count > 1)
+       return FALSE;
+ 
+-- 
+2.7.4
+
diff --git a/meta/recipes-graphics/mesa/mesa.inc b/meta/recipes-graphics/mesa/mesa.inc
index 014044f381..04285f209a 100644
--- a/meta/recipes-graphics/mesa/mesa.inc
+++ b/meta/recipes-graphics/mesa/mesa.inc
@@ -64,7 +64,7 @@ GALLIUMDRIVERS_LLVM = "r300,svga,nouveau${@',${GALLIUMDRIVERS_LLVM33}' if ${GALL
 GALLIUMDRIVERS_append_x86 = "${@bb.utils.contains('PACKAGECONFIG', 'gallium-llvm', ',${GALLIUMDRIVERS_LLVM}', '', d)}"
 GALLIUMDRIVERS_append_x86-64 = "${@bb.utils.contains('PACKAGECONFIG', 'gallium-llvm', ',${GALLIUMDRIVERS_LLVM}', '', d)}"
 # keep --with-gallium-drivers separate, because when only one of gallium versions is enabled, other 2 were adding --without-gallium-drivers
-PACKAGECONFIG[gallium]      = "--with-gallium-drivers=${GALLIUMDRIVERS}, --without-gallium-drivers"
+PACKAGECONFIG[gallium]      = "--enable-texture-float --with-gallium-drivers=${GALLIUMDRIVERS}, --without-gallium-drivers"
 MESA_LLVM_RELEASE ?= "3.3"
 PACKAGECONFIG[gallium-llvm] = "--enable-gallium-llvm --enable-llvm-shared-libs, --disable-gallium-llvm, llvm${MESA_LLVM_RELEASE} \
                                ${@'elfutils' if ${GALLIUMDRIVERS_LLVM33_ENABLED} else ''}"
diff --git a/meta/recipes-graphics/mesa/mesa_17.1.1.bb b/meta/recipes-graphics/mesa/mesa_17.1.1.bb
index 060a279015..ff84015aee 100644
--- a/meta/recipes-graphics/mesa/mesa_17.1.1.bb
+++ b/meta/recipes-graphics/mesa/mesa_17.1.1.bb
@@ -5,6 +5,7 @@ SRC_URI = "ftp://ftp.freedesktop.org/pub/mesa/mesa-${PV}.tar.xz \
            file://disable-asm-on-non-gcc.patch \
            file://0001-Use-wayland-scanner-in-the-path.patch \
            file://0001-util-rand_xor-add-missing-include-statements.patch \
+           file://0002-hardware-gloat.patch \
 "
 
 SRC_URI[md5sum] = "a4844bc6052578574f9629458bcbb749"
-- 
2.13.0