You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
129 lines
4.5 KiB
129 lines
4.5 KiB
What are these headers ?
|
|
------------------------
|
|
This is the canonical source of drm headers that user space should use for
|
|
communicating with the kernel DRM subsystem.
|
|
|
|
They flow from the kernel, thus any changes must be merged there first.
|
|
Do _not_ attempt to "fix" these by deviating from the kernel ones !
|
|
|
|
|
|
Non-linux platforms - changes/patches
|
|
-------------------------------------
|
|
If your platform has local changes, please send them upstream for inclusion.
|
|
Even if your patches don't get accepted in their current form, devs will
|
|
give you feedback on how to address things properly.
|
|
|
|
git send-email --subject-prefix="PATCH libdrm" your patches to dri-devel
|
|
mailing list.
|
|
|
|
Before doing so, please consider the following:
|
|
- Have the [libdrm vs kernel] headers on your platform deviated ?
|
|
Consider unifying them first.
|
|
|
|
- Have you introduced additional ABI that's not available in Linux ?
|
|
Propose it for [Linux kernel] upstream inclusion.
|
|
If that doesn't work out (hopefully it never does), move it to another header
|
|
and/or keep the change(s) local ?
|
|
|
|
- Are your changes DRI1/UMS specific ?
|
|
There is virtually no interest/power in keeping those legacy interfaces. They
|
|
are around due to the kernel "thou shalt not break existing user space" rule.
|
|
|
|
Consider porting the driver to DRI2/KMS - all (almost?) sensible hardware is
|
|
capable of supporting those.
|
|
|
|
|
|
Which headers go where ?
|
|
------------------------
|
|
A snipped from the, now removed, Makefile.am used to state:
|
|
|
|
XXX airlied says, nothing besides *_drm.h and drm*.h should be necessary.
|
|
however, r300 and via need their reg headers installed in order to build.
|
|
better solutions are welcome.
|
|
|
|
Obviously the r300 and via headers are no longer around ;-)
|
|
|
|
Reason behind is that the drm headers can be used as a basic communications
|
|
channel with the respective kernel modules. If more advanced functionality is
|
|
required one can pull the specific libdrm_$driver which is free to pull
|
|
additional files from the kernel.
|
|
|
|
For example: nouveau has nouveau/nvif/*.h while vc4 has vc4/*.h
|
|
|
|
If your driver is still in prototyping/staging state, consider moving the
|
|
$driver_drm.h into $driver and _not_ installing it. An header providing opaque
|
|
definitions and access [via $driver_drmif.h or similar] would be better fit.
|
|
|
|
|
|
When and which headers to update
|
|
--------------------------------
|
|
Ideally all files will be synced (updated) with the latest released kernel on
|
|
each libdrm release. Sadly that's not yet possible since quite a few headers
|
|
differ significantly - see Outdated or Broken Headers section below.
|
|
|
|
That said, it's up-to the individual developers to sync with newer version
|
|
(from drm-next) as they see fit.
|
|
|
|
|
|
When and how to update these files
|
|
----------------------------------
|
|
Note: One should not do _any_ changes to the files apart from the steps below.
|
|
|
|
In order to update the files do the following:
|
|
- Switch to a Linux kernel tree/branch which is not rebased.
|
|
For example: drm-next (https://cgit.freedesktop.org/drm/drm)
|
|
- Install the headers via `make headers_install' to a separate location.
|
|
- Copy the drm header[s] + git add + git commit.
|
|
- Note: Your commit message must include:
|
|
a) Brief summary on the delta. If there's any change that looks like an
|
|
API/ABI break one _must_ explicitly state why it's safe to do so.
|
|
b) "Generated using make headers_install."
|
|
c) "Generated from $tree/branch commit $sha"
|
|
|
|
|
|
Outdated or Broken Headers
|
|
--------------------------
|
|
This section contains a list of headers and the respective "issues" they might
|
|
have relative to their kernel equivalent.
|
|
|
|
Most UMS headers:
|
|
- Not using fixed size integers - compat ioctls are broken.
|
|
Status: ?
|
|
Promote to fixed size ints, which match the current (32bit) ones.
|
|
|
|
nouveau_drm.h
|
|
- Missing macros NOUVEAU_GETPARAM*, NOUVEAU_DRM_HEADER_PATCHLEVEL, structs,
|
|
enums
|
|
Status: Deliberate UABI choice; nouveau hides the exact kernel ABI behind libdrm
|
|
|
|
r128_drm.h
|
|
- Broken compat ioctls.
|
|
|
|
radeon_drm.h
|
|
- Missing RADEON_TILING_R600_NO_SCANOUT, CIK_TILE_MODE_*, broken UMS ioctls
|
|
- Both kernel and libdrm: missing padding -
|
|
drm_radeon_gem_{create,{g,s}et_tiling,set_domain} others ?
|
|
Status: ?
|
|
|
|
savage_drm.h
|
|
- Renamed ioctls - DRM_IOCTL_SAVAGE_{,BCI}_EVENT_EMIT, compat ioctls are broken.
|
|
Status: ?
|
|
|
|
sis_drm.h
|
|
- Borken ioctls + libdrm uses int vs kernel long
|
|
Status: ?
|
|
|
|
via_drm.h
|
|
- Borken ioctls - libdrm int vs kernel long
|
|
Status: ?
|
|
|
|
|
|
omap_drm.h (living in $TOP/omap)
|
|
- License mismatch, missing DRM_IOCTL_OMAP_GEM_NEW and related struct
|
|
Status: ?
|
|
|
|
exynos_drm.h (living in $TOP/exynos)
|
|
- License mismatch, now using fixed size ints (but not everywhere). Lots of
|
|
new stuff.
|
|
Status: ?
|