[SRU][P][PATCH 1/1] drm/amd/display: Add and use new dm_prepare_suspend() callback

[En-Wei Wu]

From: Mario Limonciello <mario.limonciello at amd.com>

BugLink: https://bugs.launchpad.net/bugs/2103480

[Why]
The displays currently don't get turned off until after other IP blocks
have been suspended.  However turning off the displays first gives a
very visible response that the system is on it's way down.

[How]
Turn off displays in a prepare_suspend() callback instead when possible.
This will help for suspend and hibernate sequences.
The shutdown sequence however will not call prepare() so check whether
the state has been already saved to decide what to do.

Acked-by: Wayne Lin <Wayne.Lin at amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
(cherry picked from commit 50e0bae34fa6b8b18e13473ddf0bcdab6ab68310 linux-next)
Signed-off-by: En-Wei Wu <en-wei.wu at canonical.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 25 ++++++++++++++++---
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 39df45f652b3..0024a574de3f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3100,6 +3100,21 @@ static void hpd_rx_irq_work_suspend(struct amdgpu_display_manager *dm)
 	}
 }
 
+static int dm_prepare_suspend(struct amdgpu_ip_block *ip_block)
+{
+	struct amdgpu_device *adev = ip_block->adev;
+
+	if (amdgpu_in_reset(adev))
+		return 0;
+
+	WARN_ON(adev->dm.cached_state);
+	adev->dm.cached_state = drm_atomic_helper_suspend(adev_to_drm(adev));
+	if (IS_ERR(adev->dm.cached_state))
+		return PTR_ERR(adev->dm.cached_state);
+
+	return 0;
+}
+
 static int dm_suspend(struct amdgpu_ip_block *ip_block)
 {
 	struct amdgpu_device *adev = ip_block->adev;
@@ -3125,10 +3140,11 @@ static int dm_suspend(struct amdgpu_ip_block *ip_block)
 		return ret;
 	}
 
-	WARN_ON(adev->dm.cached_state);
-	adev->dm.cached_state = drm_atomic_helper_suspend(adev_to_drm(adev));
-	if (IS_ERR(adev->dm.cached_state))
-		return PTR_ERR(adev->dm.cached_state);
+	if (!adev->dm.cached_state) {
+		adev->dm.cached_state = drm_atomic_helper_suspend(adev_to_drm(adev));
+		if (IS_ERR(adev->dm.cached_state))
+			return PTR_ERR(adev->dm.cached_state);
+	}
 
 	s3_handle_hdmi_cec(adev_to_drm(adev), true);
 
@@ -3542,6 +3558,7 @@ static const struct amd_ip_funcs amdgpu_dm_funcs = {
 	.early_fini = amdgpu_dm_early_fini,
 	.hw_init = dm_hw_init,
 	.hw_fini = dm_hw_fini,
+	.prepare_suspend = dm_prepare_suspend,
 	.suspend = dm_suspend,
 	.resume = dm_resume,
 	.is_idle = dm_is_idle,
-- 
2.43.0