1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/rs400.c b/drivers/gpu/drm/radeon/rs400.c
index b8074a8ec75a..9566b5940a5a 100644
--- a/drivers/gpu/drm/radeon/rs400.c
+++ b/drivers/gpu/drm/radeon/rs400.c
@@ -274,19 +274,26 @@ static void rs400_mc_init(struct radeon_device *rdev)
 
 uint32_t rs400_mc_rreg(struct radeon_device *rdev, uint32_t reg)
 {
+        unsigned long flags;
         uint32_t r;
 
+        spin_lock_irqsave(&rdev->mc_idx_lock, flags);
         WREG32(RS480_NB_MC_INDEX, reg & 0xff);
         r = RREG32(RS480_NB_MC_DATA);
         WREG32(RS480_NB_MC_INDEX, 0xff);
+        spin_unlock_irqrestore(&rdev->mc_idx_lock, flags);
         return r;
 }
 
 void rs400_mc_wreg(struct radeon_device *rdev, uint32_t reg, uint32_t v)
 {
+        unsigned long flags;
+
+        spin_lock_irqsave(&rdev->mc_idx_lock, flags);
         WREG32(RS480_NB_MC_INDEX, ((reg) & 0xff) | RS480_NB_MC_IND_WR_EN);
         WREG32(RS480_NB_MC_DATA, (v));
         WREG32(RS480_NB_MC_INDEX, 0xff);
+        spin_unlock_irqrestore(&rdev->mc_idx_lock, flags);
 }
 
 #if defined(CONFIG_DEBUG_FS)