From c745fe611ca42295c9d91d8e305d27983e9132ef Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Mon, 9 Dec 2013 17:46:59 -0500
Subject: [PATCH] drm/radeon/dpm: disable ss on Cayman

Spread spectrum seems to cause hangs when dynamic clock
switching is enabled.  Disable it for now. This does not
affect performance or the amount of power saved. Tracked
down by Martin Andersson.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=69723

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/radeon/rv770_dpm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/radeon/rv770_dpm.c b/drivers/gpu/drm/radeon/rv770_dpm.c
index 913b025ae9b3..374499db20c7 100644
--- a/drivers/gpu/drm/radeon/rv770_dpm.c
+++ b/drivers/gpu/drm/radeon/rv770_dpm.c
@@ -2328,6 +2328,12 @@ void rv770_get_engine_memory_ss(struct radeon_device *rdev)
 	pi->mclk_ss = radeon_atombios_get_asic_ss_info(rdev, &ss,
 						       ASIC_INTERNAL_MEMORY_SS, 0);
 
+	/* disable ss, causes hangs on some cayman boards */
+	if (rdev->family == CHIP_CAYMAN) {
+		pi->sclk_ss = false;
+		pi->mclk_ss = false;
+	}
+
 	if (pi->sclk_ss || pi->mclk_ss)
 		pi->dynamic_ss = true;
 	else
-- 
2.30.2