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

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.

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index b7ca4c51462120fab3ab146dd74f653e8bcb91cb..a7fdfa4f0857b3a416e67d79007a1da731455b80 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1463,6 +1463,21 @@ int radeon_device_init(struct radeon_device *rdev,
        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);