From 5f81941c9d47f783e834028dcfb8548809da5a53 Mon Sep 17 00:00:00 2001
From: Martin Habets <errandir_news@mph.eclipse.co.uk>
Date: Tue, 29 May 2007 01:11:57 -0700
Subject: [PATCH] [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>
---
 arch/sparc/Kconfig       | 7 +++++++
 drivers/char/drm/Kconfig | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

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
-- 
2.20.1