This is a note to let you know that I've just added the patch titled
drm/amd: Disable S/G for APUs when 64GB or more host memory
to the 6.5-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-amd-disable-s-g-for-apus-when-64gb-or-more-host-.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 74e920410b79e1694a692f5daa73617a0e8b8fe5
Author: Mario Limonciello <mario.limonciello@xxxxxxx>
Date: Thu Jul 27 10:22:20 2023 -0500
drm/amd: Disable S/G for APUs when 64GB or more host memory
[ Upstream commit 70e64c4d522b732e31c6475a3be2349de337d321 ]
Users report a white flickering screen on multiple systems that
is tied to having 64GB or more memory. When S/G is enabled pages
will get pinned to both VRAM carve out and system RAM leading to
this.
Until it can be fixed properly, disable S/G when 64GB of memory or
more is detected. This will force pages to be pinned into VRAM.
This should fix white screen flickers but if VRAM pressure is
encountered may lead to black screens. It's a trade-off for now.
Fixes: 81d0bcf99009 ("drm/amdgpu: make display pinning more flexible (v2)")
Cc: Hamza Mahfooz <Hamza.Mahfooz@xxxxxxx>
Cc: Roman Li <roman.li@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 6.1.y: bf0207e172703 ("drm/amdgpu: add S/G display parameter")
Cc: <stable@xxxxxxxxxxxxxxx> # 6.4.y
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2735
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2354
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index a3b86b86dc477..6dc950c1b6893 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1296,6 +1296,7 @@ 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 2168dc92c6704..6e5e4603a51a1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1461,6 +1461,32 @@ 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 e0d556cf919f7..8d09f262c14a3 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1642,9 +1642,8 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
}
break;
}
- 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)
+ init_data.flags.gpu_vm_support = amdgpu_sg_display_supported(adev);
if (init_data.flags.gpu_vm_support)
adev->mode_info.gpu_vm_support = true;
