[SPARC]: Mark as emulating cmpxchg, add appropriate depends for DRM.

The DRM code depends on an atomic version of cmpxchg(), which is not
available on sparc32. Since other platforms besides sparc32 have this
issue a KCONFIG option is added for it.

Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index bd992c0048f0aa1d8801b6dde2b3380982268ef9..fbcc00c6c06ea6dff4c0706ac86a5806b1b63b4e 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -178,6 +178,13 @@ config ARCH_HAS_ILOG2_U64
        bool
        default n
 
+config EMULATED_CMPXCHG
+       bool
+       default y
+       help
+         Sparc32 does not have a CAS instruction like sparc64. cmpxchg()
+         is emulated, and therefore it is not completely atomic.
+
 config SUN_PM
        bool
        default y

diff --git a/drivers/char/drm/Kconfig b/drivers/char/drm/Kconfig
index ef833a1c27eb1c60a49eca9566f8d987add2d262..0b7ffa5191c64e3c22433e3303c841265cc20a0d 100644 (file)
--- a/drivers/char/drm/Kconfig
+++ b/drivers/char/drm/Kconfig
@@ -6,7 +6,7 @@
 #
 config DRM
        tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)"
-       depends on (AGP || AGP=n) && PCI
+       depends on (AGP || AGP=n) && PCI && !EMULATED_CMPXCHG
        help
          Kernel-level support for the Direct Rendering Infrastructure (DRI)
          introduced in XFree86 4.0. If you say Y here, you need to select