From: Alex Deucher <alexander.deucher@amd.com>
Date: Mon, 17 Nov 2014 20:08:17 +0000 (-0500)
Subject: drm/radeon: work around a hw bug in MGCG on CIK
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4bb62c95a7e781a238b2ab374f34b1bf91e01ddc;p=linux-beck.git

drm/radeon: work around a hw bug in MGCG on CIK

Always need to set bit 0 of RLC_CGTT_MGCG_OVERRIDE
to avoid unreliable doorbell updates in some cases.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
---

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index bce73b6203ac..cef4cb7e5438 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -6344,6 +6344,7 @@ static void cik_enable_mgcg(struct radeon_device *rdev, bool enable)
 		}
 
 		orig = data = RREG32(RLC_CGTT_MGCG_OVERRIDE);
+		data |= 0x00000001;
 		data &= 0xfffffffd;
 		if (orig != data)
 			WREG32(RLC_CGTT_MGCG_OVERRIDE, data);
@@ -6377,7 +6378,7 @@ static void cik_enable_mgcg(struct radeon_device *rdev, bool enable)
 		}
 	} else {
 		orig = data = RREG32(RLC_CGTT_MGCG_OVERRIDE);
-		data |= 0x00000002;
+		data |= 0x00000003;
 		if (orig != data)
 			WREG32(RLC_CGTT_MGCG_OVERRIDE, data);