diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index bd992c0048f..fbcc00c6c06 100644
--- 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 ef833a1c27e..0b7ffa5191c 100644
--- 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