drm/radeon: disable mclk dpm on R7 260X

commit 57700ad1 upstream.

Setting higher mclks seems to cause stability issues
on some R7 260X boards.  Disable it for now for stability
until we find a proper fix.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=75992Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/gpu/drm/radeon/ci_dpm.c

@@ -5098,6 +5098,10 @@ int ci_dpm_init(struct radeon_device *rdev)
 	pi->mclk_dpm_key_disabled = 0;
 	pi->pcie_dpm_key_disabled = 0;
 
+	/* mclk dpm is unstable on some R7 260X cards */
+	if (rdev->pdev->device == 0x6658)
+		pi->mclk_dpm_key_disabled = 1;
+
 	pi->caps_sclk_ds = true;
 
 	pi->mclk_strobe_mode_threshold = 40000;