drm/radeon/kms/pm: fix power state indexing on igp chips in dynpm mode

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=28745

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 90f28175a7bc44f0180947b1ea00ebea5bc6b765..3d6645ce21518a640dd0981e38a67e223e86a49e 100644 (file)
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -130,9 +130,14 @@ void r600_pm_get_dynpm_state(struct radeon_device *rdev)
                                                        break;
                                                }
                                        }
-                               } else
-                                       rdev->pm.requested_power_state_index =
-                                               rdev->pm.current_power_state_index - 1;
+                               } else {
+                                       if (rdev->pm.current_power_state_index == 0)
+                                               rdev->pm.requested_power_state_index =
+                                                       rdev->pm.num_power_states - 1;
+                                       else
+                                               rdev->pm.requested_power_state_index =
+                                                       rdev->pm.current_power_state_index - 1;
+                               }
                        }
                        rdev->pm.requested_clock_mode_index = 0;
                        /* don't use the power state if crtcs are active and no display flag is set */