[PATCH 4/4] Revert "drm/amd/display: disable S/G display on DCN 3.1.5"

[Zhang, Yifan]

[Public]

This series is 

Reviewed-by: Yifan Zhang <yifan1.zhang at amd.com>


-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Alex Deucher
Sent: Thursday, February 9, 2023 10:12 PM
To: amd-gfx at lists.freedesktop.org
Cc: Deucher, Alexander <Alexander.Deucher at amd.com>
Subject: [PATCH 4/4] Revert "drm/amd/display: disable S/G display on DCN 3.1.5"

This reverts commit 3cc67fe1b3aa1ac4720e002f2aa2d08c9199a584.

Some users have reported flickerng with S/G display.  We've tried extensively to reproduce and debug the issue on a wide variety of platform configurations (DRAM bandwidth, etc.) and a variety of monitors, but so far have not been able to.  We disabled S/G display on a number of platforms to address this but that leads to failure to pin framebuffers errors and blank displays when there is memory pressure or no displays at all on systems with limited carveout (e.g., Chromebooks).
We have a parameter to disable this as a debugging option as a way for users to disable this, depending on their use case, and for us to help debug this further.  Having this enabled seems like the lesser of to evils.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 +
 1 file changed, 1 insertion(+)

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 f7ba65fd8f48..7f16be84f3b1 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1571,6 +1571,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 		case IP_VERSION(3, 1, 2):
 		case IP_VERSION(3, 1, 3):
 		case IP_VERSION(3, 1, 4):
+		case IP_VERSION(3, 1, 5):
 		case IP_VERSION(3, 1, 6):
 			init_data.flags.gpu_vm_support = true;
 			break;
--
2.39.1