configure: Conditionally build libdrm_intel

Only build libdrm_intel automatically if we have support for atomic
operations. To force configure to build drm pass --enable-intel, which
will cause the configure to error if no support is found. Or pass
--disable-intel to explicitly prevent libdrm_intel from being built.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/configure.ac b/configure.ac
index 870c05675b37ace39d3ca57f7a48111ddff6a652..0c216cea5c0569315490595fc4ecc9046b428cbd 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -45,8 +45,8 @@ AC_ARG_ENABLE(udev,   AS_HELP_STRING([--enable-udev],
 
 AC_ARG_ENABLE(intel,
              AS_HELP_STRING([--disable-intel],
-             [Enable support for intel's KMS API (default: enabled)]),
-             [INTEL=$enableval], [INTEL=yes])
+             [Enable support for intel's KMS API (default: auto)]),
+             [INTEL=$enableval], [INTEL=auto])
 
 AC_ARG_ENABLE(nouveau-experimental-api,
              AS_HELP_STRING([--enable-nouveau-experimental-api],
@@ -151,9 +151,7 @@ if test "x$HAVE_LIBUDEV" = xyes; then
 fi
 AM_CONDITIONAL(HAVE_LIBUDEV, [test "x$HAVE_LIBUDEV" = xyes])
 
-AM_CONDITIONAL(HAVE_INTEL, [test "x$INTEL" = xyes])
-
-if test "x$INTEL" = xyes; then
+if test "x$INTEL" != "xno"; then
     # Check for atomic intrinsics
     AC_CACHE_CHECK([for native atomic primitives], drm_cv_atomic_primitives,
     [
@@ -170,8 +168,19 @@ if test "x$INTEL" = xyes; then
            AC_DEFINE(HAVE_INTEL_ATOMIC_PRIMITIVES, 1,
                      [Enable if your compiler supports the Intel __sync_* atomic primitives])
     fi
+
+    if test "x$drm_cv_atomic_primitives" = "xnone"; then
+           if test "x$INTEL" != "xauto"; then
+                   AC_MSG_ERROR([libdrm_intel depends upon atomic operations, which were not found for your compiler/cpu. Try compiling with -march=native, or disable support for Intel GPUs by passing --disable-intel to ./configue])
+          else
+                   INTEL=no
+          fi
+    fi
 fi
 
+AM_CONDITIONAL(HAVE_INTEL, [test "x$INTEL" != "xno"])
+
+
 AC_SUBST(WARN_CFLAGS)
 AC_OUTPUT([
        Makefile