On Thu, May 1, 2025 at 11:17 PM Mario Limonciello <supe...@kernel.org> wrote:
>
> From: Mario Limonciello <mario.limoncie...@amd.com>
>
> commit 2965e6355dcd ("drm/amd: Add Suspend/Hibernate notification
> callback support") introduced a VRAM eviction earlier in the PM
> sequences when swap was still available for evicting to. This helped
> to fix a number of memory pressure related bugs but also exposed a
> new one.
>
> If a userspace process is actively using the GPU when suspend starts
> then a deadlock could occur.
>
> Instead of going off the prepare notifier, use the PM notifiers that
> occur after processes have been frozen to do evictions.
>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4178
> Fixes: 2965e6355dcd ("drm/amd: Add Suspend/Hibernate notification callback
> support")
> Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 7f354cd532dc1..cad311b9fd834 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4917,10 +4917,10 @@ static int amdgpu_device_pm_notifier(struct
> notifier_block *nb, unsigned long mo
> int r;
>
> switch (mode) {
> - case PM_HIBERNATION_PREPARE:
> + case PM_HIBERNATION_POST_FREEZE:
> adev->in_s4 = true;
> fallthrough;
> - case PM_SUSPEND_PREPARE:
> + case PM_SUSPEND_POST_FREEZE:
> r = amdgpu_device_evict_resources(adev);
> /*
> * This is considered non-fatal at this time because
> --
Why do you need a notifier for this?
It looks like this could be done from amdgpu_device_prepare(), but if
there is a reason why it cannot be done from there, it should be
mentioned in the changelog.
