linux-kernel - [PATCH 3.13.y-ckt 077/143] drm/radeon: workaround for CP HW bug on CIK

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Date:	Tue, 31 Mar 2015 12:47:22 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Christian König <christian.koenig@....com>,
	Alex Deucher <alexander.deucher@....com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13.y-ckt 077/143] drm/radeon: workaround for CP HW bug on CIK

3.13.11-ckt18 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@....com>

commit a9c73a0e022c33954835e66fec3cd744af90ec98 upstream.

Emit the EOP twice to avoid cache flushing problems.

Signed-off-by: Christian König <christian.koenig@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 drivers/gpu/drm/radeon/cik.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index de0652e..37b79f2 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -3513,7 +3513,21 @@ void cik_fence_gfx_ring_emit(struct radeon_device *rdev,
 	struct radeon_ring *ring = &rdev->ring[fence->ring];
 	u64 addr = rdev->fence_drv[fence->ring].gpu_addr;
 
-	/* EVENT_WRITE_EOP - flush caches, send int */
+	/* Workaround for cache flush problems. First send a dummy EOP
+	 * event down the pipe with seq one below.
+	 */
+	radeon_ring_write(ring, PACKET3(PACKET3_EVENT_WRITE_EOP, 4));
+	radeon_ring_write(ring, (EOP_TCL1_ACTION_EN |
+				 EOP_TC_ACTION_EN |
+				 EVENT_TYPE(CACHE_FLUSH_AND_INV_TS_EVENT) |
+				 EVENT_INDEX(5)));
+	radeon_ring_write(ring, addr & 0xfffffffc);
+	radeon_ring_write(ring, (upper_32_bits(addr) & 0xffff) |
+				DATA_SEL(1) | INT_SEL(0));
+	radeon_ring_write(ring, fence->seq - 1);
+	radeon_ring_write(ring, 0);
+
+	/* Then send the real EOP event down the pipe. */
 	radeon_ring_write(ring, PACKET3(PACKET3_EVENT_WRITE_EOP, 4));
 	radeon_ring_write(ring, (EOP_TCL1_ACTION_EN |
 				 EOP_TC_ACTION_EN |
-- 
1.9.1

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