mirror of
https://github.com/torvalds/linux.git
synced 2024-11-28 07:01:32 +00:00
f5a8d8774b
The new cool is &struct foo (kernel-doc now copes with linebreaks), and structure members should be referenced using &foo.bar. Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-8-git-send-email-daniel.vetter@ffwll.ch
53 lines
2.6 KiB
ReStructuredText
53 lines
2.6 KiB
ReStructuredText
============
|
|
Introduction
|
|
============
|
|
|
|
The Linux DRM layer contains code intended to support the needs of
|
|
complex graphics devices, usually containing programmable pipelines well
|
|
suited to 3D graphics acceleration. Graphics drivers in the kernel may
|
|
make use of DRM functions to make tasks like memory management,
|
|
interrupt handling and DMA easier, and provide a uniform interface to
|
|
applications.
|
|
|
|
A note on versions: this guide covers features found in the DRM tree,
|
|
including the TTM memory manager, output configuration and mode setting,
|
|
and the new vblank internals, in addition to all the regular features
|
|
found in current kernels.
|
|
|
|
[Insert diagram of typical DRM stack here]
|
|
|
|
Style Guidelines
|
|
================
|
|
|
|
For consistency this documentation uses American English. Abbreviations
|
|
are written as all-uppercase, for example: DRM, KMS, IOCTL, CRTC, and so
|
|
on. To aid in reading, documentations make full use of the markup
|
|
characters kerneldoc provides: @parameter for function parameters,
|
|
@member for structure members (within the same structure), &struct structure to
|
|
reference structures and function() for functions. These all get automatically
|
|
hyperlinked if kerneldoc for the referenced objects exists. When referencing
|
|
entries in function vtables (and structure members in general) please use
|
|
&vtable_name.vfunc. Unfortunately this does not yet yield a direct link to the
|
|
member, only the structure.
|
|
|
|
Except in special situations (to separate locked from unlocked variants)
|
|
locking requirements for functions aren't documented in the kerneldoc.
|
|
Instead locking should be check at runtime using e.g.
|
|
``WARN_ON(!mutex_is_locked(...));``. Since it's much easier to ignore
|
|
documentation than runtime noise this provides more value. And on top of
|
|
that runtime checks do need to be updated when the locking rules change,
|
|
increasing the chances that they're correct. Within the documentation
|
|
the locking rules should be explained in the relevant structures: Either
|
|
in the comment for the lock explaining what it protects, or data fields
|
|
need a note about which lock protects them, or both.
|
|
|
|
Functions which have a non-\ ``void`` return value should have a section
|
|
called "Returns" explaining the expected return values in different
|
|
cases and their meanings. Currently there's no consensus whether that
|
|
section name should be all upper-case or not, and whether it should end
|
|
in a colon or not. Go with the file-local style. Other common section
|
|
names are "Notes" with information for dangerous or tricky corner cases,
|
|
and "FIXME" where the interface could be cleaned up.
|
|
|
|
Also read the :ref:`guidelines for the kernel documentation at large <doc_guide>`.
|