linux-kernel - [PATCH v2 2/2] Revert "drm/amd: Disable S/G for APUs when 64GB or more host memory"

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Message-ID: <20230908145521.39044-2-hamza.mahfooz@amd.com>
Date:   Fri, 8 Sep 2023 10:55:13 -0400
From:   Hamza Mahfooz <hamza.mahfooz@....com>
To:     <amd-gfx@...ts.freedesktop.org>
CC:     Hamza Mahfooz <hamza.mahfooz@....com>, <stable@...r.kernel.org>,
        "Alex Deucher" <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@....com>,
        Lijo Lazar <lijo.lazar@....com>,
        Hawking Zhang <Hawking.Zhang@....com>, Le Ma <le.ma@....com>,
        Candice Li <candice.li@....com>, Lang Yu <Lang.Yu@....com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Victor Zhao <Victor.Zhao@....com>,
        "Mario Limonciello" <mario.limonciello@....com>,
        Srinivasan Shanmugam <srinivasan.shanmugam@....com>,
        Shashank Sharma <shashank.sharma@....com>,
        Qingqing Zhuo <Qingqing.Zhuo@....com>,
        Aurabindo Pillai <aurabindo.pillai@....com>,
        Hersen Wu <hersenxs.wu@....com>,
        Stylon Wang <stylon.wang@....com>,
        Wayne Lin <wayne.lin@....com>, Alan Liu <haoping.liu@....com>,
        Luben Tuikov <luben.tuikov@....com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 2/2] Revert "drm/amd: Disable S/G for APUs when 64GB or more host memory"

This reverts commit 5b7a256c982636ebc4f16b708b40ff56d33c8a86.

Since, we now have an actual fix for this issue, we can get rid of this
workaround as it can cause pin failures if enough VRAM isn't carved out
by the BIOS.

Cc: stable@...r.kernel.org # 6.1+
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@....com>
---
v2: new to the series
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h           |  1 -
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    | 26 -------------------
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  5 ++--
 3 files changed, 3 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 83a9607a87b8..3a86d11d1605 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1316,7 +1316,6 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
 void amdgpu_device_pci_config_reset(struct amdgpu_device *adev);
 int amdgpu_device_pci_reset(struct amdgpu_device *adev);
 bool amdgpu_device_need_post(struct amdgpu_device *adev);
-bool amdgpu_sg_display_supported(struct amdgpu_device *adev);
 bool amdgpu_device_pcie_dynamic_switching_supported(void);
 bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev);
 bool amdgpu_device_aspm_support_quirk(void);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5f32e8d4f3d3..3d540b0cf0e1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1358,32 +1358,6 @@ bool amdgpu_device_need_post(struct amdgpu_device *adev)
 	return true;
 }
 
-/*
- * On APUs with >= 64GB white flickering has been observed w/ SG enabled.
- * Disable S/G on such systems until we have a proper fix.
- * https://gitlab.freedesktop.org/drm/amd/-/issues/2354
- * https://gitlab.freedesktop.org/drm/amd/-/issues/2735
- */
-bool amdgpu_sg_display_supported(struct amdgpu_device *adev)
-{
-	switch (amdgpu_sg_display) {
-	case -1:
-		break;
-	case 0:
-		return false;
-	case 1:
-		return true;
-	default:
-		return false;
-	}
-	if ((totalram_pages() << (PAGE_SHIFT - 10)) +
-	    (adev->gmc.real_vram_size / 1024) >= 64000000) {
-		DRM_WARN("Disabling S/G due to >=64GB RAM\n");
-		return false;
-	}
-	return true;
-}
-
 /*
  * Intel hosts such as Raptor Lake and Sapphire Rapids don't support dynamic
  * speed switching. Until we have confirmation from Intel that a specific host
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 5f14cd9391ca..740a6fcafe4c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1654,8 +1654,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 		}
 		break;
 	}
-	if (init_data.flags.gpu_vm_support)
-		init_data.flags.gpu_vm_support = amdgpu_sg_display_supported(adev);
+	if (init_data.flags.gpu_vm_support &&
+	    (amdgpu_sg_display == 0))
+		init_data.flags.gpu_vm_support = false;
 
 	if (init_data.flags.gpu_vm_support)
 		adev->mode_info.gpu_vm_support = true;
-- 
2.41.0