Merge tag 'drm-for-v4.11-less-shouty' of git://people.freedesktop.org/~airlied/linux

Pull drm updates from Dave Airlie:
 "This is the main drm pull request for v4.11.

  Nothing too major, the tinydrm and mmu-less support should make
  writing smaller drivers easier for some of the simpler platforms, and
  there are a bunch of documentation updates.

  Intel grew displayport MST audio support which is hopefully useful to
  people, and FBC is on by default for GEN9+ (so people know where to
  look for regressions). AMDGPU has a lot of fixes that would like new
  firmware files installed for some GPUs.

  Other than that it's pretty scattered all over.

  I may have a follow up pull request as I know BenH has a bunch of AST
  rework and fixes and I'd like to get those in once they've been tested
  by AST, and I've got at least one pull request I'm just trying to get
  the author to fix up.

  Core:
   - drm_mm reworked
   - Connector list locking and iterators
   - Documentation updates
   - Format handling rework
   - MMU-less support for fbdev helpers
   - drm_crtc_from_index helper
   - Core CRC API
   - Remove drm_framebuffer_unregister_private
   - Debugfs cleanup
   - EDID/Infoframe fixes
   - Release callback
   - Tinydrm support (smaller drivers for simple hw)

  panel:
   - Add support for some new simple panels

  i915:
   - FBC by default for gen9+
   - Shared dpll cleanups and docs
   - GEN8 powerdomain cleanup
   - DMC support on GLK
   - DP MST audio support
   - HuC loading support
   - GVT init ordering fixes
   - GVT IOMMU workaround fix

  amdgpu/radeon:
   - Power/clockgating improvements
   - Preliminary SR-IOV support
   - TTM buffer priority and eviction fixes
   - SI DPM quirks removed due to firmware fixes
   - Powerplay improvements
   - VCE/UVD powergating fixes
   - Cleanup SI GFX code to match CI/VI
   - Support for > 2 displays on 3/5 crtc asics
   - SI headless fixes

  nouveau:
   - Rework securre boot code in prep for GP10x secure boot
   - Channel recovery improvements
   - Initial power budget code
   - MMU rework preperation

  vmwgfx:
   - Bunch of fixes and cleanups

  exynos:
   - Runtime PM support for MIC driver
   - Cleanups to use atomic helpers
   - UHD Support for TM2/TM2E boards
   - Trigger mode fix for Rinato board

  etnaviv:
   - Shader performance fix
   - Command stream validator fixes
   - Command buffer suballocator

  rockchip:
   - CDN DisplayPort support
   - IOMMU support for arm64 platform

  imx-drm:
   - Fix i.MX5 TV encoder probing
   - Remove lower fb size limits

  msm:
   - Support for HW cursor on MDP5 devices
   - DSI encoder cleanup
   - GPU DT bindings cleanup

  sti:
   - stih410 cleanups
   - Create fbdev at binding
   - HQVDP fixes
   - Remove stih416 chip functionality
   - DVI/HDMI mode selection fixes
   - FPS statistic reporting

  omapdrm:
   - IRQ code cleanup

  dwi-hdmi bridge:
   - Cleanups and fixes

  adv-bridge:
   - Updates for nexus

  sii8520 bridge:
   - Add interlace mode support
   - Rework HDMI and lots of fixes

  qxl:
   - probing/teardown cleanups

  ZTE drm:
   - HDMI audio via SPDIF interface
   - Video Layer overlay plane support
   - Add TV encoder output device

  atmel-hlcdc:
   - Rework fbdev creation logic

  tegra:
   - OF node fix

  fsl-dcu:
   - Minor fixes

  mali-dp:
   - Assorted fixes

  sunxi:
   - Minor fix"

[ This was the "fixed" pull, that still had build warnings due to people
  not even having build tested the result. I'm not a happy camper

  I've fixed the things I noticed up in this merge.      - Linus ]

* tag 'drm-for-v4.11-less-shouty' of git://people.freedesktop.org/~airlied/linux: (1177 commits)
  lib/Kconfig: make PRIME_NUMBERS not user selectable
  drm/tinydrm: helpers: Properly fix backlight dependency
  drm/tinydrm: mipi-dbi: Fix field width specifier warning
  drm/tinydrm: mipi-dbi: Silence: ‘cmd’ may be used uninitialized
  drm/sti: fix build warnings in sti_drv.c and sti_vtg.c files
  drm/amd/powerplay: fix PSI feature on Polars12
  drm/amdgpu: refuse to reserve io mem for split VRAM buffers
  drm/ttm: fix use-after-free races in vm fault handling
  drm/tinydrm: Add support for Multi-Inno MI0283QT display
  dt-bindings: Add Multi-Inno MI0283QT binding
  dt-bindings: display/panel: Add common rotation property
  of: Add vendor prefix for Multi-Inno
  drm/tinydrm: Add MIPI DBI support
  drm/tinydrm: Add helper functions
  drm: Add DRM support for tiny LCD displays
  drm/amd/amdgpu: post card if there is real hw resetting performed
  drm/nouveau/tmr: provide backtrace when a timeout is hit
  drm/nouveau/pci/g92: Fix rearm
  drm/nouveau/drm/therm/fan: add a fallback if no fan control is specified in the vbios
  drm/nouveau/hwmon: expose power_max and power_crit
  ..

1 files changed, 92 insertions, 0 deletions

diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index a9b457a4b949..31671b469627 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -17,6 +17,98 @@ shared or exclusive fence(s) associated with the buffer.
 Shared DMA Buffers
 ------------------
 
+This document serves as a guide to device-driver writers on what is the dma-buf
+buffer sharing API, how to use it for exporting and using shared buffers.
+
+Any device driver which wishes to be a part of DMA buffer sharing, can do so as
+either the 'exporter' of buffers, or the 'user' or 'importer' of buffers.
+
+Say a driver A wants to use buffers created by driver B, then we call B as the
+exporter, and A as buffer-user/importer.
+
+The exporter
+
+ - implements and manages operations in :c:type:`struct dma_buf_ops
+   <dma_buf_ops>` for the buffer,
+ - allows other users to share the buffer by using dma_buf sharing APIs,
+ - manages the details of buffer allocation, wrapped int a :c:type:`struct
+   dma_buf <dma_buf>`,
+ - decides about the actual backing storage where this allocation happens,
+ - and takes care of any migration of scatterlist - for all (shared) users of
+   this buffer.
+
+The buffer-user
+
+ - is one of (many) sharing users of the buffer.
+ - doesn't need to worry about how the buffer is allocated, or where.
+ - and needs a mechanism to get access to the scatterlist that makes up this
+   buffer in memory, mapped into its own address space, so it can access the
+   same area of memory. This interface is provided by :c:type:`struct
+   dma_buf_attachment <dma_buf_attachment>`.
+
+Any exporters or users of the dma-buf buffer sharing framework must have a
+'select DMA_SHARED_BUFFER' in their respective Kconfigs.
+
+Userspace Interface Notes
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Mostly a DMA buffer file descriptor is simply an opaque object for userspace,
+and hence the generic interface exposed is very minimal. There's a few things to
+consider though:
+
+- Since kernel 3.12 the dma-buf FD supports the llseek system call, but only
+  with offset=0 and whence=SEEK_END|SEEK_SET. SEEK_SET is supported to allow
+  the usual size discover pattern size = SEEK_END(0); SEEK_SET(0). Every other
+  llseek operation will report -EINVAL.
+
+  If llseek on dma-buf FDs isn't support the kernel will report -ESPIPE for all
+  cases. Userspace can use this to detect support for discovering the dma-buf
+  size using llseek.
+
+- In order to avoid fd leaks on exec, the FD_CLOEXEC flag must be set
+  on the file descriptor.  This is not just a resource leak, but a
+  potential security hole.  It could give the newly exec'd application
+  access to buffers, via the leaked fd, to which it should otherwise
+  not be permitted access.
+
+  The problem with doing this via a separate fcntl() call, versus doing it
+  atomically when the fd is created, is that this is inherently racy in a
+  multi-threaded app[3].  The issue is made worse when it is library code
+  opening/creating the file descriptor, as the application may not even be
+  aware of the fd's.
+
+  To avoid this problem, userspace must have a way to request O_CLOEXEC
+  flag be set when the dma-buf fd is created.  So any API provided by
+  the exporting driver to create a dmabuf fd must provide a way to let
+  userspace control setting of O_CLOEXEC flag passed in to dma_buf_fd().
+
+- Memory mapping the contents of the DMA buffer is also supported. See the
+  discussion below on `CPU Access to DMA Buffer Objects`_ for the full details.
+
+- The DMA buffer FD is also pollable, see `Fence Poll Support`_ below for
+  details.
+
+Basic Operation and Device DMA Access
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/dma-buf.c
+   :doc: dma buf device access
+
+CPU Access to DMA Buffer Objects
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/dma-buf.c
+   :doc: cpu access
+
+Fence Poll Support
+~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/dma-buf/dma-buf.c
+   :doc: fence polling
+
+Kernel Functions and Structures Reference
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
 .. kernel-doc:: drivers/dma-buf/dma-buf.c
    :export: