[75/80] drm/radeon/kms/atom: fix possible segfault in pm setup

[Greg KH]

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

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Content-Length: 1216
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From: =?UTF-8?q?Alexander=20M=C3=BCller?= <serveralex@xxxxxxxxx>

commit 4376eee92e5a8332b470040e672ea99cd44c826a upstream.

If we end up with no power states, don't look up
current vddc.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=44130

agd5f: fix patch formatting

Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/gpu/drm/radeon/radeon_atombios.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -2568,7 +2568,11 @@ void radeon_atombios_get_power_modes(str
 
 	rdev->pm.current_power_state_index = rdev->pm.default_power_state_index;
 	rdev->pm.current_clock_mode_index = 0;
-	rdev->pm.current_vddc = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.voltage;
+	if (rdev->pm.default_power_state_index >= 0)
+		rdev->pm.current_vddc =
+			rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.voltage;
+	else
+		rdev->pm.current_vddc = 0;
 }
 
 void radeon_atom_set_clock_gating(struct radeon_device *rdev, int enable)


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