Merge tag 'drm-next-2020-10-15' of git://anongit.freedesktop.org/drm/drm

Pull drm updates from Dave Airlie:
 "Not a major amount of change, the i915 trees got split into display
  and gt trees to better facilitate higher level review, and there's a
  major refactoring of i915 GEM locking to use more core kernel concepts
  (like ww-mutexes). msm gets per-process pagetables, older AMD SI cards
  get DC support, nouveau got a bump in displayport support with common
  code extraction from i915.

  Outside of drm this contains a couple of patches for hexint
  moduleparams which you've acked, and a virtio common code tree that
  you should also get via it's regular path.

  New driver:
   - Cadence MHDP8546 DisplayPort bridge driver

  core:
   - cross-driver scatterlist cleanups
   - devm_drm conversions
   - remove drm_dev_init
   - devm_drm_dev_alloc conversion

  ttm:
   - lots of refactoring and cleanups

  bridges:
   - chained bridge support in more drivers

  panel:
   - misc new panels

  scheduler:
   - cleanup priority levels

  displayport:
   - refactor i915 code into helpers for nouveau

  i915:
   - split into display and GT trees
   - WW locking refactoring in GEM
   - execbuf2 extension mechanism
   - syncobj timeline support
   - GEN 12 HOBL display powersaving
   - Rocket Lake display additions
   - Disable FBC on Tigerlake
   - Tigerlake Type-C + DP improvements
   - Hotplug interrupt refactoring

  amdgpu:
   - Sienna Cichlid updates
   - Navy Flounder updates
   - DCE6 (SI) support for DC
   - Plane rotation enabled
   - TMZ state info ioctl
   - PCIe DPC recovery support
   - DC interrupt handling refactor
   - OLED panel fixes

  amdkfd:
   - add SMI events for thermal throttling
   - SMI interface events ioctl update
   - process eviction counters

  radeon:
   - move to dma_ for allocations
   - expose sclk via sysfs

  msm:
   - DSI support for sm8150/sm8250
   - per-process GPU pagetable support
   - Displayport support

  mediatek:
   - move HDMI phy driver to PHY
   - convert mtk-dpi to bridge API
   - disable mt2701 tmds

  tegra:
   - bridge support

  exynos:
   - misc cleanups

  vc4:
   - dual display cleanups

  ast:
   - cleanups

  gma500:
   - conversion to GPIOd API

  hisilicon:
   - misc reworks

  ingenic:
   - clock handling and format improvements

  mcde:
   - DSI support

  mgag200:
   - desktop g200 support

  mxsfb:
   - i.MX7 + i.MX8M
   - alpha plane support

  panfrost:
   - devfreq support
   - amlogic SoC support

  ps8640:
   - EDID from eDP retrieval

  tidss:
   - AM65xx YUV workaround

  virtio:
   - virtio-gpu exported resources

  rcar-du:
   - R8A7742, R8A774E1 and R8A77961 support
   - YUV planar format fixes
   - non-visible plane handling
   - VSP device reference count fix
   - Kconfig fix to avoid displaying disabled options in .config"

* tag 'drm-next-2020-10-15' of git://anongit.freedesktop.org/drm/drm: (1494 commits)
  drm/ingenic: Fix bad revert
  drm/amdgpu: Fix invalid number of character '{' in amdgpu_acpi_init
  drm/amdgpu: Remove warning for virtual_display
  drm/amdgpu: kfd_initialized can be static
  drm/amd/pm: setup APU dpm clock table in SMU HW initialization
  drm/amdgpu: prevent spurious warning
  drm/amdgpu/swsmu: fix ARC build errors
  drm/amd/display: Fix OPTC_DATA_FORMAT programming
  drm/amd/display: Don't allow pstate if no support in blank
  drm/panfrost: increase readl_relaxed_poll_timeout values
  MAINTAINERS: Update entry for st7703 driver after the rename
  Revert "gpu/drm: ingenic: Add option to mmap GEM buffers cached"
  drm/amd/display: HDMI remote sink need mode validation for Linux
  drm/amd/display: Change to correct unit on audio rate
  drm/amd/display: Avoid set zero in the requested clk
  drm/amdgpu: align frag_end to covered address space
  drm/amdgpu: fix NULL pointer dereference for Renoir
  drm/vmwgfx: fix regression in thp code due to ttm init refactor.
  drm/amdgpu/swsmu: add interrupt work handler for smu11 parts
  drm/amdgpu/swsmu: add interrupt work function
  ...

1 files changed, 113 insertions, 1 deletions

diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
index 496d8fcd4da0..7dce175f6d75 100644
--- a/Documentation/gpu/drm-uapi.rst
+++ b/Documentation/gpu/drm-uapi.rst
@@ -1,3 +1,5 @@
+.. Copyright 2020 DisplayLink (UK) Ltd.
+
 ===================
 Userland interfaces
 ===================
@@ -162,6 +164,116 @@ other hand, a driver requires shared state between clients which is
 visible to user-space and accessible beyond open-file boundaries, they
 cannot support render nodes.
 
+Device Hot-Unplug
+=================
+
+.. note::
+   The following is the plan. Implementation is not there yet
+   (2020 May).
+
+Graphics devices (display and/or render) may be connected via USB (e.g.
+display adapters or docking stations) or Thunderbolt (e.g. eGPU). An end
+user is able to hot-unplug this kind of devices while they are being
+used, and expects that the very least the machine does not crash. Any
+damage from hot-unplugging a DRM device needs to be limited as much as
+possible and userspace must be given the chance to handle it if it wants
+to. Ideally, unplugging a DRM device still lets a desktop continue to
+run, but that is going to need explicit support throughout the whole
+graphics stack: from kernel and userspace drivers, through display
+servers, via window system protocols, and in applications and libraries.
+
+Other scenarios that should lead to the same are: unrecoverable GPU
+crash, PCI device disappearing off the bus, or forced unbind of a driver
+from the physical device.
+
+In other words, from userspace perspective everything needs to keep on
+working more or less, until userspace stops using the disappeared DRM
+device and closes it completely. Userspace will learn of the device
+disappearance from the device removed uevent, ioctls returning ENODEV
+(or driver-specific ioctls returning driver-specific things), or open()
+returning ENXIO.
+
+Only after userspace has closed all relevant DRM device and dmabuf file
+descriptors and removed all mmaps, the DRM driver can tear down its
+instance for the device that no longer exists. If the same physical
+device somehow comes back in the mean time, it shall be a new DRM
+device.
+
+Similar to PIDs, chardev minor numbers are not recycled immediately. A
+new DRM device always picks the next free minor number compared to the
+previous one allocated, and wraps around when minor numbers are
+exhausted.
+
+The goal raises at least the following requirements for the kernel and
+drivers.
+
+Requirements for KMS UAPI
+-------------------------
+
+- KMS connectors must change their status to disconnected.
+
+- Legacy modesets and pageflips, and atomic commits, both real and
+  TEST_ONLY, and any other ioctls either fail with ENODEV or fake
+  success.
+
+- Pending non-blocking KMS operations deliver the DRM events userspace
+  is expecting. This applies also to ioctls that faked success.
+
+- open() on a device node whose underlying device has disappeared will
+  fail with ENXIO.
+
+- Attempting to create a DRM lease on a disappeared DRM device will
+  fail with ENODEV. Existing DRM leases remain and work as listed
+  above.
+
+Requirements for Render and Cross-Device UAPI
+---------------------------------------------
+
+- All GPU jobs that can no longer run must have their fences
+  force-signalled to avoid inflicting hangs on userspace.
+  The associated error code is ENODEV.
+
+- Some userspace APIs already define what should happen when the device
+  disappears (OpenGL, GL ES: `GL_KHR_robustness`_; `Vulkan`_:
+  VK_ERROR_DEVICE_LOST; etc.). DRM drivers are free to implement this
+  behaviour the way they see best, e.g. returning failures in
+  driver-specific ioctls and handling those in userspace drivers, or
+  rely on uevents, and so on.
+
+- dmabuf which point to memory that has disappeared will either fail to
+  import with ENODEV or continue to be successfully imported if it would
+  have succeeded before the disappearance. See also about memory maps
+  below for already imported dmabufs.
+
+- Attempting to import a dmabuf to a disappeared device will either fail
+  with ENODEV or succeed if it would have succeeded without the
+  disappearance.
+
+- open() on a device node whose underlying device has disappeared will
+  fail with ENXIO.
+
+.. _GL_KHR_robustness: https://www.khronos.org/registry/OpenGL/extensions/KHR/KHR_robustness.txt
+.. _Vulkan: https://www.khronos.org/vulkan/
+
+Requirements for Memory Maps
+----------------------------
+
+Memory maps have further requirements that apply to both existing maps
+and maps created after the device has disappeared. If the underlying
+memory disappears, the map is created or modified such that reads and
+writes will still complete successfully but the result is undefined.
+This applies to both userspace mmap()'d memory and memory pointed to by
+dmabuf which might be mapped to other devices (cross-device dmabuf
+imports).
+
+Raising SIGBUS is not an option, because userspace cannot realistically
+handle it. Signal handlers are global, which makes them extremely
+difficult to use correctly from libraries like those that Mesa produces.
+Signal handlers are not composable, you can't have different handlers
+for GPU1 and GPU2 from different vendors, and a third handler for
+mmapped regular files. Threads cause additional pain with signal
+handling as well.
+
 .. _drm_driver_ioctl:
 
 IOCTL Support on Device Nodes
@@ -199,7 +311,7 @@ EPERM/EACCES:
         difference between EACCES and EPERM.
 
 ENODEV:
-        The device is not (yet) present or fully initialized.
+        The device is not present anymore or is not yet fully initialized.
 
 EOPNOTSUPP:
         Feature (like PRIME, modesetting, GEM) is not supported by the driver.