Merge tag 'drm-misc-next-2023-09-11-1' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for v6.7-rc1:

UAPI Changes:
- Nouveau changed to not set NO_PREFETCH flag explicitly.

Cross-subsystem Changes:
- Update documentation of dma-buf intro and uapi.
- fbdev/sbus fixes.
- Use initializer macros in a lot of fbdev drivers.
- Add Boris Brezillon as Panfrost driver maintainer.
- Add Jessica Zhang as drm/panel reviewer.
- Make more fbdev drivers use fb_ops helpers for deferred io.
- Small hid trailing whitespace fix.
- Use fb_ops in hid/picolcd

Core Changes:
- Assorted small fixes to ttm tests, drm/mst.
- Documentation updates to bridge.
- Add kunit tests for some drm_fb functions.
- Rework drm_debugfs implementation.
- Update xe documentation to mark todos as completed.

Driver Changes:
- Add support to rockchip for rv1126 mipi-dsi and vop.
- Assorted small fixes to nouveau, bridge/samsung-dsim,
  bridge/lvds-codec, loongson, rockchip, panfrost, gma500, repaper,
  komeda, virtio, ssd130x.
- Add support for simple panels Mitsubishi AA084XE01,
  JDI LPM102A188A,
- Documentation updates to accel/ivpu.
- Some nouveau scheduling/fence fixes.
- Power management related fixes and other fixes to ivpu.
- Assorted bridge/it66121 fixes.
- Make platform drivers return void in remove() callback.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3da6554b-3b47-fe7d-c4ea-21f4f819dbb6@linux.intel.com

1 files changed, 24 insertions, 8 deletions

diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index f92a32d095d9..0c153d79ccc4 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -5,14 +5,30 @@ The dma-buf subsystem provides the framework for sharing buffers for
 hardware (DMA) access across multiple device drivers and subsystems, and
 for synchronizing asynchronous hardware access.
 
-This is used, for example, by drm "prime" multi-GPU support, but is of
-course not limited to GPU use cases.
-
-The three main components of this are: (1) dma-buf, representing a
-sg_table and exposed to userspace as a file descriptor to allow passing
-between devices, (2) fence, which provides a mechanism to signal when
-one device has finished access, and (3) reservation, which manages the
-shared or exclusive fence(s) associated with the buffer.
+As an example, it is used extensively by the DRM subsystem to exchange
+buffers between processes, contexts, library APIs within the same
+process, and also to exchange buffers with other subsystems such as
+V4L2.
+
+This document describes the way in which kernel subsystems can use and
+interact with the three main primitives offered by dma-buf:
+
+ - dma-buf, representing a sg_table and exposed to userspace as a file
+   descriptor to allow passing between processes, subsystems, devices,
+   etc;
+ - dma-fence, providing a mechanism to signal when an asynchronous
+   hardware operation has completed; and
+ - dma-resv, which manages a set of dma-fences for a particular dma-buf
+   allowing implicit (kernel-ordered) synchronization of work to
+   preserve the illusion of coherent access
+
+
+Userspace API principles and use
+--------------------------------
+
+For more details on how to design your subsystem's API for dma-buf use, please
+see Documentation/userspace-api/dma-buf-alloc-exchange.rst.
+
 
 Shared DMA Buffers
 ------------------