libdrm: improve atomic handling, fix SPARCv8 build

This commit improves the handling of the "atomic stuff" in the libdrm
package. libdrm can either use the atomic intrinsics (4 byte variant)
when available, or otherwise can use libatomic_ops. Note that the
dependency on atomic operations is not from libdrm itself, but only
from some specific DRM drivers only.

Amongst other things, it fixes the build of the libdrm package on
SPARCv8, therefore fixing:

  http://autobuild.buildroot.org/results/74dd29b5ea146c320fde80a87a2fc910de9b7f60/

This commit does a number of changes that are all related to each
other:

 - Removes the dependency of the Intel DRM driver on
   libatomic_ops. The Intel DRM driver builds perfectly fine without
   libatomic_ops, as long as 4-byte variant __sync operations are
   available, which is always the case on x86 and x86_84 (which are
   the only architectures on which the Intel DRM driver can be
   enabled).

 - Adds an hidden Config.in boolean option
   BR2_PACKAGE_LIBDRM_HAS_ATOMIC that allows DRM driver that need
   atomic operation to know whether atomic support is available
   (either through intrinsics or through libatomic_ops).

 - Adds an hidden BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC Config.in option
   that DRM drivers that need atomic operation should select to ensure
   that the relevant dependencies are selected. It simply selects
   libatomic_ops if 4-byte atomic intrinsics are not available. We
   could let each DRM driver do this, but having an intermediate
   option avoids a bit of duplication.

 - Adds a patch that defines AO_REQUIRE_CAS before including
   <atomic_ops.h>. This is needed because libdrm uses the
   AO_compare_and_swap_full() which is only provided on all
   architectures when AO_REQUIRE_CAS is defined. The exact same fix
   was done in the erlang package in commit
   4a9df2942470241d7a96f326f0e7012aacd36f2e.

 - Adds the dependency on libatomic_ops when the package is enabled,
   and passes the necessary CFLAGS on SPARCv8 to make the thing build
   properly. The same CFLAGS are passed in the nginx package and bdwgc
   package.

Cc: Waldemar Brodkorb <wbx@openadk.org>
Cc: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

diff --git a/package/libdrm/0003-xf86atomic-require-CAS-support-in-libatomic_ops.patch b/package/libdrm/0003-xf86atomic-require-CAS-support-in-libatomic_ops.patch
new file mode 100644 (file)
index 0000000..ff920fb
--- /dev/null
+++ b/package/libdrm/0003-xf86atomic-require-CAS-support-in-libatomic_ops.patch
@@ -0,0 +1,32 @@
+From 7384f79f69fdb7b691cc5b0c28c301b3fe8b633e Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Date: Thu, 26 May 2016 10:46:57 +0200
+Subject: [PATCH] xf86atomic: require CAS support in libatomic_ops
+
+Since AO_compare_and_swap_full() is used by libdrm, AO_REQUIRE_CAS
+must be defined before including <atomic_ops.h> so that we are sure
+that CAS support will be provided. This is necessary to make sure that
+the AO_compare_and_swap_full() function will be provided on all
+architectures, including the ones that don't have built-in CAS support
+such as SPARCv8.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+---
+ xf86atomic.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/xf86atomic.h b/xf86atomic.h
+index 922b37d..d7017a5 100644
+--- a/xf86atomic.h
++++ b/xf86atomic.h
+@@ -58,6 +58,7 @@ typedef struct {
+ #endif
+ 
+ #if HAVE_LIB_ATOMIC_OPS
++#define AO_REQUIRE_CAS
+ #include <atomic_ops.h>
+ 
+ #define HAS_ATOMIC_OPS 1
+-- 
+2.7.4
+

diff --git a/package/libdrm/Config.in b/package/libdrm/Config.in
index 343a2ed5918bb2e43c5074b918f875b7b710dc1b..7c2a82859fb03b81c257b9d926df18b746f4b8d0 100644 (file)
--- a/package/libdrm/Config.in
+++ b/package/libdrm/Config.in
@@ -9,6 +9,15 @@ config BR2_PACKAGE_LIBDRM
 
 if BR2_PACKAGE_LIBDRM
 
+config BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       bool
+       default y if BR2_PACKAGE_LIBATOMIC_OPS_ARCH_SUPPORTS || \
+               BR2_TOOLCHAIN_HAS_SYNC_4
+
+config BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
+       bool
+       select BR2_PACKAGE_LIBATOMIC_OPS if !BR2_TOOLCHAIN_HAS_SYNC_4
+
 config BR2_PACKAGE_LIBDRM_INSTALL_TESTS
        bool "Install test programs"
        help
@@ -18,24 +27,31 @@ menu "DRM Drivers"
 
 config BR2_PACKAGE_LIBDRM_INTEL
        bool "intel"
-       select BR2_PACKAGE_LIBATOMIC_OPS
        select BR2_PACKAGE_LIBPCIACCESS
        depends on BR2_i386 || BR2_x86_64
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install intel graphics driver.
 
 config BR2_PACKAGE_LIBDRM_RADEON
        bool "radeon"
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install AMD/ATI graphics driver.
 
 config BR2_PACKAGE_LIBDRM_AMDGPU
        bool "amdgpu"
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install AMD GPU driver.
 
 config BR2_PACKAGE_LIBDRM_NOUVEAU
        bool "nouveau"
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install NVIDIA graphics driver.
 
@@ -48,6 +64,8 @@ config BR2_PACKAGE_LIBDRM_VMWGFX
 config BR2_PACKAGE_LIBDRM_OMAP
        bool "omap (experimental)"
        depends on BR2_arm
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install the TI OMAP driver using an experimental API.
 
@@ -60,12 +78,16 @@ config BR2_PACKAGE_LIBDRM_EXYNOS
 config BR2_PACKAGE_LIBDRM_FREEDRENO
        bool "freedreno"
        depends on BR2_arm || BR2_aarch64 || BR2_aarch64_be
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install Qualcomm Snapdragon driver.
 
 config BR2_PACKAGE_LIBDRM_TEGRA
        bool "tegra (experimental)"
        depends on BR2_arm
+       depends on BR2_PACKAGE_LIBDRM_HAS_ATOMIC
+       select BR2_PACKAGE_LIBDRM_ENABLE_ATOMIC
        help
          Install NVIDIA Tegra driver using an experimental API.
 

diff --git a/package/libdrm/libdrm.mk b/package/libdrm/libdrm.mk
index 1d41f0591276524f112e71b316ec9bff30a8b136..50fa7ef92f08e6ab71d4fe05509e7ff7311e3617 100644 (file)
--- a/package/libdrm/libdrm.mk
+++ b/package/libdrm/libdrm.mk
@@ -21,9 +21,16 @@ LIBDRM_CONF_OPTS = \
 
 LIBDRM_CONF_ENV = ac_cv_prog_cc_c99='-std=gnu99'
 
+ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y)
+LIBDRM_DEPENDENCIES += libatomic_ops
+ifeq ($(BR2_sparc_v8)$(BR2_sparc_leon3),y)
+LIBDRM_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -DAO_NO_SPARC_V9"
+endif
+endif
+
 ifeq ($(BR2_PACKAGE_LIBDRM_INTEL),y)
 LIBDRM_CONF_OPTS += --enable-intel
-LIBDRM_DEPENDENCIES += libatomic_ops libpciaccess
+LIBDRM_DEPENDENCIES += libpciaccess
 else
 LIBDRM_CONF_OPTS += --disable-intel
 endif