From: Dongwon Kim <dongwon....@intel.com>

This patch series implements functions for .freeze and .restore hooks for
virtio-gpu driver as well as pm-notifier to handle object restoration in
S4(hiberation) case.

First patch adds `virtgpu_freeze` and `virtgpu_restore` functions.
These functions handle the deletion of virtio queues before suspension and
their recreation during the restoration process.

Second patch implements a mechanism for restoring `virtio_gpu_object` instances.
This is necessary because the host (QEMU) deletes all associated resources 
during
the virtio-gpu reset, which occurs as part of hiberation/resume process.

Third patch adds pm-notifier to the driver that handles resubmission of 
virtio-gpu
objects to the QEMU once the guest resumes from hibenation.

These changes ensure that the virtio-gpu driver can properly handle hibernation
scenarios without resource loss.

v2: 10ms sleep is added in virtgpu_freeze to avoid the situation
    the driver is locked up during resumption.

v3: Plain 10ms delay (v2) is replaced with wait calls which wait until
    the virtio queue is empty.
    (Dmitry Osipenko)

v4: New version of patchset only covers S4 case because loss of resources in S3
    case can be avoided by skipping virtio-gpu-reset in QEMU 
(hw/display/virtio-gpu.c).
    To skip virtio-gpu-reset (soft-reset), virtio-gpu-pci device should be 
attached to
    PCIE bus AND a PCIE option, 'x-pcie-pm-no-soft-reset' should added and set 
to 'true'.
    (e.g. -device virtio-gpu-pci,bus=port,x-pcie-pm-no-soft-reset=true)

v5: Remove virtio_gpu_object from the restore list before freeing the object
    to prevent an use-after-free situation.
    (Nirmoy Das)

    Protect restore list operations with a spinlock
    (Nirmoy Das)

    Move restore list node into virtio_gpu_bo struct to reduce memory usage
    (Dmitry Osipenko)

    Remove unused header - drm_atomic_helper.h 
    (Dmitry Osipenko)

Dongwon Kim (3):
  drm/virtio: Freeze and restore hooks to support suspend and resume
  drm/virtio: Add support for saving and restoring virtio_gpu_objects
  drm/virtio: Add PM notifier to restore objects after hibernation

 drivers/gpu/drm/virtio/virtgpu_drv.c    | 60 +++++++++++++++++++++++-
 drivers/gpu/drm/virtio/virtgpu_drv.h    | 12 +++++
 drivers/gpu/drm/virtio/virtgpu_kms.c    | 51 ++++++++++++++++++---
 drivers/gpu/drm/virtio/virtgpu_object.c | 61 +++++++++++++++++++++++++
 4 files changed, 177 insertions(+), 7 deletions(-)

-- 
2.34.1

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