linux_dsm_epyc7002/Documentation/gpu
Daniel Vetter 9e1ed9fb1e drm: Add docs for managed resources
All collected together to provide a consistent story in one patch,
instead of the somewhat bumpy refactor-evolution leading to this.

Also some thoughts on what the next steps could be:

- Create a macro called devm_drm_dev_alloc() which essentially wraps
  the kzalloc(); devm_drm_dev_init(); drmm_add_final_kfree() combo.
  Needs to be a macro since we'll have to do some typeof trickery and
  casting to make this fully generic for all drivers that embed struct
  drm_device into their own thing.

- A lot of the simple drivers now have essentially just
  drm_dev_unplug(); drm_atomic_helper_shutdown(); as their
  $bus_driver->remove hook. We could create a devm_mode_config_reset
  which sets drm_atomic_helper_shutdown as it's cleanup action, and a
  devm_drm_dev_register with drm_dev_unplug as it's cleanup action,
  and simple drivers wouldn't have a need for a ->remove function at
  all, and we could delete them.

- For more complicated drivers we need drmm_ versions of a _lot_ more
  things. All the userspace visible objects (crtc, plane, encoder,
  crtc), anything else hanging of those (maybe a drmm_get_edid, at
  least for panels and other built-in stuff).

Also some more thoughts on why we're not reusing devm_ with maybe a
fake struct device embedded into the drm_device (we can't use the
kdev, since that's in each drm_minor).

- Code review gets extremely tricky, since every time you see a devm_
  you need to carefully check whether the fake device (with the
  drm_device lifetim) or the real device (with the lifetim of the
  underlying physical device and driver binding) are used. That's not
  going to help at all, and we have enormous amounts of drivers who
  use devm_ where they really shouldn't. Having different types makes
  sure the compiler type checks this for us and ensures correctness.

- The set of functions are very much non-overlapping. E.g.
  devm_ioremap makes total sense, drmm_ioremap has the wrong lifetime,
  since hw resources need to be cleaned out at driver unbind and wont
  outlive that like a drm_device. Similar, but other way round for
  drmm_connector_init (which is the only correct version, devm_ for
  drm_connector is just buggy). Simply not having the wrong version
  again prevents bugs.

Finally I guess this opens a huge todo for all the drivers. I'm
semi-tempted to do a tree-wide s/devm_kzalloc/drmm_kzalloc/ since most
likely that'll fix an enormous amount of bugs and most likely not
cause any issues at all (aside from maybe holding onto memory slightly
too long).

v2:
- Doc improvements from Laurent.
- Also add kerneldoc for the new drmm_add_action_or_reset.

v3:
- Remove kerneldoc for drmm_remove_action.

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

fixup docs
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-52-daniel.vetter@ffwll.ch
2020-03-26 16:09:48 +01:00
..
bridge drm: bridge: dw-hdmi: Add Documentation on supported input formats 2017-04-04 17:48:21 +02:00
dp-mst drm/dp_mst: Introduce new refcounting scheme for mstbs and ports 2019-01-10 20:12:19 -05:00
afbc.rst drm/afbc: Add AFBC modifier usage documentation 2019-01-11 17:52:06 +00:00
amdgpu-dc.rst drm/amd/display: Initial documentation for AMDgpu DC 2018-11-05 14:21:37 -05:00
amdgpu.rst drm/amdgpu: Improve RAS documentation (v2) 2019-11-06 16:27:48 -05:00
drivers.rst drm/tinydrm: Move mipi-dbi 2019-07-25 10:45:07 +02:00
drm-client.rst drm/fb-helper: Remove drm_fb_helper_crtc 2019-06-04 12:13:47 +02:00
drm-internals.rst drm: Add docs for managed resources 2020-03-26 16:09:48 +01:00
drm-kms-helpers.rst drm: Add helper to create a connector for a chain of bridges 2020-02-26 13:31:41 +02:00
drm-kms.rst drm: Manage drm_mode_config_init with drmm_ 2020-03-26 15:45:43 +01:00
drm-mm.rst drm/doc: Drop :c:func: markup 2019-12-10 21:44:02 +01:00
drm-uapi.rst drm/doc: Add VKMS module description and use to "Testing and Validation" 2019-12-05 18:52:12 -05:00
i915.rst drm/i915: Fix doclinks 2020-03-03 09:56:43 +00:00
index.rst drm: Begin an API for in-kernel clients 2018-07-10 14:51:37 +02:00
introduction.rst drm/doc: Document kapi doc expectations 2019-07-19 15:02:37 +02:00
kms-properties.csv drm/doc: Drop "content type" from the legacy kms property table 2019-03-26 14:18:51 +01:00
komeda-kms.rst drm/doc: Add initial komeda driver documentation 2019-01-14 11:20:11 +00:00
mcde.rst drm/mcde: Fix reference to DOC comment 2019-10-05 20:35:14 +02:00
meson.rst Documentation/gpu/meson: Remove link to meson_canvas.c 2019-04-05 08:35:05 -04:00
msm-crash-dump.rst docs: mark orphan documents as such 2019-06-08 13:42:11 -06:00
pl111.rst drm/pl111: Initial drm/kms driver for pl111 2017-05-08 12:24:06 -07:00
tegra.rst drm/tegra: Add driver documentation 2017-06-15 13:58:56 +02:00
todo.rst drm/core: Add drm_afbc_framebuffer and a corresponding helper 2020-03-18 11:22:05 +01:00
tve200.rst drm/tve200: fix kernel-doc documentation comment include 2018-02-21 09:26:38 +02:00
v3d.rst drm/v3d: Add missing v3d documentation structure. 2018-07-05 11:42:50 -07:00
vc4.rst drm/vc4: Add a paragraph at the top of vc4 docs introducing what it is. 2017-02-28 12:51:49 -08:00
vga-switcheroo.rst drm/doc: Fix vga_switcheroo xref 2016-08-24 13:11:08 +02:00
vgaarbiter.rst vgaarbiter: rst-ifiy and polish kerneldoc 2016-08-16 18:49:56 +02:00
vkms.rst drm/doc: Remove solved "VBlank issues" 2019-02-06 21:40:56 +01:00
xen-front.rst drm/xen-front: Remove CMA support 2018-04-18 10:18:27 +03:00