Patch "drm/radeon: fix freeze for laptop with Turks/Thames GPU." has been added to the 4.0-stable tree

This is a note to let you know that I've just added the patch titled

drm/radeon: fix freeze for laptop with Turks/Thames GPU.

to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-radeon-fix-freeze-for-laptop-with-turks-thames-gpu.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= <[email protected]>
Date: Fri, 5 Jun 2015 13:33:57 -0400
Subject: drm/radeon: fix freeze for laptop with Turks/Thames GPU.
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From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= <[email protected]>

commit 6dfd197283bffc23a2b046a7f065588de7e1fc1e upstream.

Laptop with Turks/Thames GPU will freeze if dpm is enabled. It seems the SMC engine is relying on some state inside the CP engine. CP needs to chew at least one packet for it to get in good state for dynamic power management.

This patch simply disabled and re-enable DPM after the ring test which is enough to avoid the freeze.

---
 drivers/gpu/drm/radeon/radeon_device.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

@@ -1458,6 +1458,21 @@ int radeon_device_init(struct radeon_dev
 	if (r)
 		DRM_ERROR("ib ring test failed (%d).\n", r);
 
+	/*
+	 * Turks/Thames GPU will freeze whole laptop if DPM is not restarted
+	 * after the CP ring have chew one packet at least. Hence here we stop
+	 * and restart DPM after the radeon_ib_ring_tests().
+	 */
+	if (rdev->pm.dpm_enabled &&
+	    (rdev->pm.pm_method == PM_METHOD_DPM) &&
+	    (rdev->family == CHIP_TURKS) &&
+	    (rdev->flags & RADEON_IS_MOBILITY)) {
+		mutex_lock(&rdev->pm.mutex);
+		radeon_dpm_disable(rdev);
+		radeon_dpm_enable(rdev);
+		mutex_unlock(&rdev->pm.mutex);
+	}
+
 	if ((radeon_testing & 1)) {
 		if (rdev->accel_working)
 			radeon_test_moves(rdev);

Patches currently in stable-queue which might be from [email protected] are

queue-4.0/drm-radeon-fix-freeze-for-laptop-with-turks-thames-gpu.patch --
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