drm/radeon/si_dpm: Limit clocks on HD86xx part

BugLink: http://bugs.launchpad.net/bugs/1642572

commit fb9a5b0c upstream.

Limit clocks on a specific HD86xx part to avoid
crashes (while awaiting an appropriate PP fix).
Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/gpu/drm/radeon/si_dpm.c

@@ -3021,6 +3021,12 @@ static void si_apply_state_adjust_rules(struct radeon_device *rdev,
 		max_sclk = 75000;
 		max_mclk = 80000;
 	}
+	/* limit clocks on HD8600 series */
+	if (rdev->pdev->device == 0x6660 &&
+	    rdev->pdev->revision == 0x83) {
+		max_sclk = 75000;
+		max_mclk = 80000;
+	}
 
 	if (rps->vce_active) {
 		rps->evclk = rdev->pm.dpm.vce_states[rdev->pm.dpm.vce_level].evclk;