These were introduced in the very first DRM commit:

  commit f453ba04
  Author: Dave Airlie <airlied@redhat.com>
  Date:   Fri Nov 7 14:05:41 2008 -0800

      DRM: add mode setting support

      Add mode setting support to the DRM layer.

But are unused.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

It's only used in drm_crtc.c.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

The last user was removed in

  commit 575dc34e
  Author: Dave Airlie <airlied@redhat.com>
  Date:   Mon Sep 7 18:43:26 2009 +1000

      drm/kms: remove old std mode fallback code.

      The new code adds modes in the helper, which makes more sense
      I disliked the non-driver code adding modes.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

This was last used by nouveau, replaced by a driver-specific property
in:

  commit de691855
  Author: Ben Skeggs <bskeggs@redhat.com>
  Date:   Mon Oct 17 12:23:41 2011 +1000

      drm/nouveau: improve dithering properties, and implement proper auto mode
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

A few prototypes have been left in the headers, their function friends
long gone.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

We kzalloc this structure, and for real kms devices we should never
loose track of things really.

But ums/legacy drivers rely on the drm core to clean up a bit of cruft
between lastclose and firstopen (i.e. when X is being restarted), so
keep this around. But give it a clear drm_legacy_ prefix and
conditionalize the code on !DRIVER_MODESET.

Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

So almost two years ago I've tried to nuke the procfs code already
once before:

http://lists.freedesktop.org/archives/dri-devel/2011-October/015707.html

The conclusion was that userspace drivers (specifically libdrm device
node detection) stopped relying on procfs in 2001. But after some
digging it turned out that the drmstat tool in libdrm is still using
those files (but only when certain options are set). So we've decided
to keep profcs.

But I when I've started to dig around again what exactly this tool
does I've noticed that it tries to read the "mem", "vm", and "vma"
files from procfs. Now as far my git history digging shows "mem" never
did anything useful (at least in the version that first showed up in
upstream history in 2004) and the file was remove in

commit 955b12de
Author: Ben Gamari <bgamari@gmail.com>
Date:   Tue Feb 17 20:08:49 2009 -0500

    drm: Convert proc files to seq_file and introduce debugfs

Which means that for over 4 years drmstat has been broken, and no one
cared. In my opinion that's proof enough that no one is actually using
drmstat, and so that we can savely nuke the procfs support from drm.

While at it fix up the error case cleanup for debugfs in drm_get_minor.

v2: Fix dates, libdrm stopped relying on procfs for drm node detection
in 2001.

v3: fixup compilation warning for !CONFIG_DEBUG_FS, reported by
Fengguang Wu.

Cc: kbuild test robot <fengguang.wu@intel.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

It has way too much potential for driver writers to do stupid things
like delayed hw setup because the load sequence is somehow racy (e.g.
the imx driver in staging). So don't call it for modesetting drivers,
which reduces the complexity of the drm core -> driver interface a
notch.

v2: Don't forget to update DocBook.

v3: Go with Laurent's slightly more elaborate proposal for the DocBook
update. Add a few words on top of his diff to elaborate a bit on what
KMS drivers should and shouldn't do in lastclose. There was already a
paragraph present talking about restoring properties, I've simply
extended that one.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

So if we survey kms drivers there's a bunch of things they commonly do
in ->lastclose
- delayed processing of vga switcheroo requests (i915, nouveau,
  radeon)
- force-restoring the fbcon (most)
- resetting a bunch properties to make fbcon work better (omap)
- disabling all outputs (vmwgfx)

In short besides the semantically important vga switcheroo stuff they
all try very hard to keep fbcon working in case X dies.

But none of them try to not do this at driver unload time safe for
vmwgfx, and digging through logs I couldn't find any reason for why
vmwgfx is special.

Since ->firstopen has lots of potential for abuse with kms drivers
(like delaying driver setup to pamper over races in the load sequence)
it's imo very much worth it to remove this logic so that we can
stop using the ->firstopen callback for kms drivers.

Also module unloading is rather a debug feature and developers should
know how to restore the display to a sane configuration.

Cc: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

This thing seems to do some kind of delayed setup. Really, real kms
drivers shouldn't do that at all. Either stuff needs to be dynamically
hotplugged or the driver setup sequence needs to be fixed.

This patch here just moves the setup at the very end of the driver
load callback, with the locking adjusted accordingly.

v2: Also move the corresponding put from ->lastclose to ->unload.

Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Currently, both ranges overlap. Fix the limits so both ranges are mutually
exclusive. Also use the occasion to convert whitespaces to tabs.
Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
(fixed up tabs and adjust commit-msg accordingly)
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

The idr is protected with our spinlock, if we don't hold that nothing
prevents the gem objects from disappearing from under us.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

We might as well have a real ioctl function which checks for the
callbacks. This seems to be a remnant from back in the days when each
drm driver had their own complete ioctl table, with no shared core
drm table at all.

To make really sure no mis-guided user in a kms driver pops up again
explicitly check for that in the new ioctl implementation.

v2: Drop the unused variable I've accidentally left in the code,
spotted by David Herrmann.

Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

I've forgotten this and shuffling all the little pieces into the
respective patches is rather cumbersome ...
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

The new arch_phys_wc_add/del functions do the right thing both with
and without MTRR support in the kernel. So we can drop these
additional checks.

David Herrmann suggest to also kill the DRIVER_USE_MTRR flag since
it's now unused, which spurred me to do a bit a better audit of the
affected drivers. David helped a lot in that. Quoting our mail
discussion:

On Wed, Jul 10, 2013 at 5:41 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
> On Wed, Jul 10, 2013 at 5:22 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>> On Wed, Jul 10, 2013 at 3:51 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
>>>> -#if __OS_HAS_MTRR
>>>> -static inline int drm_core_has_MTRR(struct drm_device *dev)
>>>> -{
>>>> -       return drm_core_check_feature(dev, DRIVER_USE_MTRR);
>>>> -}
>>>> -#else
>>>> -#define drm_core_has_MTRR(dev) (0)
>>>> -#endif
>>>> -
>>>
>>> That was the last user of DRIVER_USE_MTRR (apart from drivers setting
>>> it in .driver_features). Any reason to keep it around?
>>
>> Yeah, I guess we could rip things out. Which will also force me to
>> properly audit drivers for the eventual behaviour change this could
>> entail (in case there's an x86 driver which did not ask for an mtrr,
>> but iirc there isn't).
>
> david@david-mb ~/dev/kernel/linux $ for i in drivers/gpu/drm/* ; do if
> test -d "$i" ; then if ! grep -q USE_MTRR -r $i ; then echo $i ; fi ;
> fi ; done
> drivers/gpu/drm/exynos
> drivers/gpu/drm/gma500
> drivers/gpu/drm/i2c
> drivers/gpu/drm/nouveau
> drivers/gpu/drm/omapdrm
> drivers/gpu/drm/qxl
> drivers/gpu/drm/rcar-du
> drivers/gpu/drm/shmobile
> drivers/gpu/drm/tilcdc
> drivers/gpu/drm/ttm
> drivers/gpu/drm/udl
> drivers/gpu/drm/vmwgfx
> david@david-mb ~/dev/kernel/linux $
>
> So for x86 gma500,nouveau,qxl,udl,vmwgfx don't set DRIVER_USE_MTRR.
> But I cannot tell whether they break if we call arch_phys_wc_add/del,
> anyway. At least nouveau seemed to work here, but it doesn't use AGP
> or drm_bufs, I guess.

Cool, thanks a lot for stitching together the list of drivers to look
at. So for real KMS drivers it's the drives responsibility to add an
mtrr if it needs one. nouvea, radeon, mgag200, i915 and vmwgfx do that
already. Somehow the savage driver also ends up doing that, I have no
idea why.

Note that gma500 as a pure KMS driver doesn't need MTRR setup since
the platforms that it supports all support PAT. So no MTRRs needed to
get wc iomappings.

The mtrr support in the drm core is all for legacy mappings of garts,
framebuffers and registers. All legacy drivers set the USE_MTRR flag,
so we're good there.

All in all I think we can really just ditch this

/endquote

v2: Also kill DRIVER_USE_MTRR as suggested by David Herrmann

v3: Rebase on top of David Herrmann's agp setup/cleanup changes.

Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Trying to drop a reference we don't have is a pretty serious bug.
Trying to paper over it is an even worse offense.

So scream into dmesg with a big WARN in case that ever happens.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Calling this function with a NULL object is simply a bug, so papering
over a NULL object not a good idea.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

We have three callers of this function now and it's neither
performance critical nor really small. So an inline function feels
like overkill and unecessarily separates the different parts of the
code.

Since all callers of drm_gem_object_handle_free are now in drm_gem.c
we can make that static (and remove the unused EXPORT_SYMBOL). To
avoid a forward declaration move it (and drm_gem_object_free_bug) up a
bit.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Lifetime rules seem to be solid around ->import_attach. So this patch
just properly documents them.

Note that pointing directly at the attachment might have issues for
devices that have multiple struct device *dev parts constituting the
logical gpu and so might need multiple attachment points. Similarly
for drm devices which don't need a dma attachment at all (like udl).

But fixing that up is material for different patches.
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

I've checked both implementations (radeon/nouveau) and they both grab
the page array from ttm simply by dereferencing it and then wrapping
it up with drm_prime_pages_to_sg in the callback and map it with
dma_map_sg (in the helper).

Only the grabbing of the underlying page array is anything we need to
be concerned about, and either those pages are pinned independently,
or we're screwed no matter what.

And indeed, nouveau/radeon pin the backing storage in their
attach/detach functions.

Since I've created this patch cma prime support for dma_buf was added.
drm_gem_cma_prime_get_sg_table only calls kzalloc and the creates&maps
the sg table with dma_get_sgtable. It doesn't touch any gem object
state otherwise. So the cma helpers also look safe.

The only thing we might claim it does is prevent concurrent mapping of
dma_buf attachments. But a) that's not allowed and b) the current code
is racy already since it checks whether the sg mapping exists _before_
grabbing the lock.

So the dev->struct_mutex locking here does absolutely nothing useful,
but only distracts. Remove it.

This should also help Maarten's work to eventually pin the backing
storage more dynamically by preventing locking inversions around
dev->struct_mutex.

v2: Add analysis for recently added cma helper prime code.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Note that this is slightly tricky since both drivers store their
native objects in dma_buf->priv. But both also embed the base
drm_gem_object at the first position, so the implicit cast is ok.

To use the release helper we need to export it, too.

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

VMA offsets are 64bit so do not cast them to "unsigned int". Also remove
the (now useless) offset-retrieval helper. The VMA manager provides simple
enough helpers.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: "Terje Bergström" <tbergstrom@nvidia.com>
Cc: Arto Merilainen <amerilainen@nvidia.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

This makes it so that reloading a module does not cause all the
connector ids to change, which are user-visible and sometimes used
for configuration.
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Basically just extracting some code duplicated in gma500, omapdrm, udl,
and upcoming msm driver.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Variant of drm_gem_create_mmap_offset() which doesn't make the
assumption that virtual size and physical size (obj->size) are the same.
This is needed in omapdrm to deal with tiled buffers.  And lets us get
rid of a duplicated and slightly modified version of
drm_gem_create_mmap_offset() in omapdrm.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

And simplify how we hold a ref+pin to what is being scanned out by using
fb refcnt'ing.  The previous logic pre-dated fb refcnt, and as a result
was less straightforward than it could have been.  By holding a ref to
the fb, we don't have to care about how many plane's there are and
holding a ref to each color plane's bo.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Rob Clark <robdclark@gmail.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

A small helper to queue up work to do, from workqueue context, after a
flip.  Typically useful to defer unreffing buffers that may be read by
the display controller until vblank.

v1: original
v2: wire up docbook + couple docbook fixes
Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

This function is unused.
Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Again only used by a tests in libdrm and by dristat. Nowadays we have
much better tracing tools to get detailed insights into what a drm
driver is doing. And for a simple "does it work" kind of question that
these stats could answer we have plenty of dmesg debug log spew.

So I don't see any use for this stat gathering complexity at all.

To be able to gradually drop things start with ripping out the
interfaces to it, here the ioctl.

To prevent dristat from eating its own stack garbage we can't use the
drm_noop ioctl though, since we need to clear the return data with a
memset.

Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

We not only have debugfs files to do pretty much the equivalent of
lsof, we also have an ioctl. Not that compared to lsof this dumps a
wee bit more information, but we can still get at that from debugfs
easily.

I've dug around in mesa, libdrm and ddx histories and the only users
seem to be drm/tests/dristat.c and drm/tests/getclients.c. The later
is a testcase for the ioctl itself since up to

commit b018fcda
Author: Eric Anholt <eric@anholt.net>
Date:   Thu Nov 22 18:46:54 2007 +1000

    drm: Make DRM_IOCTL_GET_CLIENT return EINVAL when it can't find client #idx

there was actually no way at all for userspace to enumerate all
clients since the kernel just wouldn't tell it when to stop. Which
completely broke it's only user, dristat -c.

So obviously that ioctl wasn't much use for debugging. Hence I don't
see any point in keeping support for a tool which was pretty obviously
never really used, and while we have good replacements in the form of
equivalent debugfs files.

Still, to keep dristat -c from looping forever again stop it early by
returning an unconditional -EINVAL. Also add a comment in the code
about why.

v2: Slightly less hollowed-out implementation. libva uses GET_CLIENTS
to figure out whether the fd it has is already authenticated or not.
So we need to keep that part of things working. Simplest way is to
just return one entry to keep va_drm_is_authenticated in
libva/va/drm/va_drm_auth.c working.

This is exercised by igt/drm_get_client_auth which contains a
copypasta of the libva auth check code.

Cc: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

They're only used by the agpgart support code in drm_agpgart.c,
not by any drivers.

I think long-term we should create a drm_internal.h include file with
all the various functions only used by the drm core and not exported
to drivers, and remove them from drmP.h. Oh, and someone should kill
that upper-case P sometimes ;-) But that's all stuff for future patch
bombs.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

The gma500 driver somehow set the DRIVER_IRQ_VBL flag, but since
there's no code at all to check for this we can kill it. The other two
are completely unused.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

No driver ever sets that flag, so good riddance!
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

So I've stumbled over drm_fasync and wondered what it does. Digging
that up is quite a story.

First I've had to read up on what this does and ended up being rather
bewildered why peopled loved signals so much back in the days that
they've created SIGIO just for that ...

Then I wondered how this ever works, and what that strange "No-op."
comment right above it should mean. After all calling the core fasync
helper is pretty obviously not a noop. After reading through the
kernels FASYNC implementation I've noticed that signals are only sent
out to the processes attached with FASYNC by calling kill_fasync.

No merged drm driver has ever done that.

After more digging I've found out that the only driver that ever used
this is the so called GAMMA driver. I've frankly never heard of such a
gpu brand ever before. Now FASYNC seems to not have been the only bad
thing with that driver, since Dave Airlie removed it from the drm
driver with prejudice:

commit 1430163b4bbf7b00367ea1066c1c5fe85dbeefed
Author: Dave Airlie <airlied@linux.ie>
Date:   Sun Aug 29 12:04:35 2004 +0000

    Drop GAMMA DRM from a great height ...

Long story short, the drm fasync support seems to be doing absolutely
nothing. And the only user of it was never merged into the upstream
kernel. And we don't need any fops->fasync callback since the fcntl
implementation in the kernel already implements the noop case
correctly.

So stop this particular cargo-cult and rip it all out.

v2: Kill drm_fasync assignments in rcar (newly added) and imx drivers
(somehow I've missed that one in staging). Also drop the reference in
the drm DocBook. ARM compile-fail reported by Rob Clark.

v3: Move the removal of dev->buf_asnyc assignment in drm_setup to this
patch here.

v4: Actually git add ... tsk.

Cc: Dave Airlie <airlied@linux.ie>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Clark <robdclark@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>