Now that we added specific item to our subclassed drm_plane_state
we can add omap_plane_atomic_print_state() helper to dump out our own
driver specific plane state.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-9-narmstrong@baylibre.com

(re)assign the hw overlays to planes based on required caps, and to
handle situations where we could not modify an in-use plane.

This means all planes advertise the superset of formats and properties.
Userspace must (as always) use atomic TEST_ONLY step for atomic updates,
as not all planes may be available for use on every frame.

The mapping of hwoverlays to plane is stored in omap_global_state, so
that state updates are atomically committed in the same way that
plane/etc state updates are managed.  This is needed because the
omap_plane_state keeps a pointer to the hwoverlay, and we don't want
global state to become out of sync with the plane state if an atomic
update fails, we hit deadlock/ backoff scenario, etc.  The use of
global_state_lock keeps multiple parallel updates which both re-assign
hwoverlays properly serialized.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-8-narmstrong@baylibre.com

Global shared resources (like hw overlays) for omapdrm are implemented
as a part of atomic state using the drm_private_obj infrastructure
available in the atomic core.

omap_global_state is introduced as a drm atomic private object. The two
funcs omap_get_global_state() and omap_get_existing_global_state() are
the two variants that will be used to access omap_global_state.

drm_mode_config_init() needs to be called earlier because it
creates/initializes the private_obj link list maintained by the atomic
framework. The private_obj link list has to exist prior to calling
drm_atomic_private_obj_init(). Similarly the cleanup handler are
reordered appropriately.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-7-narmstrong@baylibre.com

In preparation to add omap plane state specific extensions we need to
subclass drm_plane_state and add the relevant helpers.

The addition of specific extension will be done separately.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-6-narmstrong@baylibre.com

Split out the hardware overlay specifics from omap_plane.
To start, the hw overlays are statically assigned to planes.

The goal is to eventually assign hw overlays dynamically to planes
during plane->atomic_check() based on requested caps (scaling, YUV,
etc). And then perform hw overlay re-assignment if required.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-5-narmstrong@baylibre.com

In order to be able to dynamically assign overlays to planes we need to
be able to asses the overlay capabilities.

Add a helper function to be able to retrieve the supported capabilities
of an overlay.

And export the function to check if a fourcc is supported on a given
overlay.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-4-narmstrong@baylibre.com

We currently assume that an overlay has the same maximum width and
maximum height as the overlay manager. This assumption is incorrect. On
some variants the overlay manager maximum width is twice the maximum
width that the overlay can handle. We need to add the appropriate data
per variant as well as export a helper function to retrieve the data so
check can be made dynamically in omap_plane_atomic_check().
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-3-narmstrong@baylibre.com

Call drm_atomic_helper_check_plane_state() from the plane
atomic_check() callback in order to add plane state sanity
checking.

It will permit filtering out totally bad scaling factors, even
if the real check are done later in the atomic commit.

Calling drm_atomic_helper_check_plane_state() also sets
plane_state->visible which will be useful when dynamically
assigning hw overlays to planes.
Signed-off-by: NBenoit Parrot <bparrot@ti.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117141928.771082-2-narmstrong@baylibre.com

Memory of BOs backed by TILER is not contiguous, but omap_gem_map_dma_buf()
exports it like it is. This leads to (possibly) invalid memory accesses if
another device imports such a BO.

Fix that by providing sg that correctly describes TILER memory layout.
Align TILER allocations to page, so importer to be able to correctly set
its MMU if have one. Set export size accounting for the alignment. Also,
make sure to destroy sg on unpin, as it is no longer valid.

Tested on Motorola Droid4 by using GPU (sgx540) to render.
Suggested-by: NMatthijs van Duin <matthijsvanduin@gmail.com>
Signed-off-by: NIvaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1637309180-31032-1-git-send-email-ivo.g.dimitrov.75@gmail.com

When we added the support for the AUX channel in commit 13afcdd7
("drm/bridge: parade-ps8640: Add support for AUX channel") we forgot
to set "drm_dev" to avoid the warning splat at the beginning of
drm_dp_aux_register(). Since everything was working I guess I never
noticed the splat when testing against mainline. In any case, it's
easy to fix. This is basically just like commit 6cba3fe4 ("drm/dp:
Add backpointer to drm_device in drm_dp_aux") but just for the
parade-ps8640.

Fixes: 13afcdd7 ("drm/bridge: parade-ps8640: Add support for AUX channel")
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Reviewed-by: NPhilip Chen <philipchen@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211206162907.1.I1f5d1eba741e4663050ec1b8e39a753f6e42e38b@changeid

At present, we have enough panel to confirm the effect,
update the initial code to achieve the best effect.
Such as gamma, Gop timing. They are all minor modifications
and doesn't affect the lighting of the panel.

a)Boe-tv110c9m panel Optimized touch horizontal grain.
b)Inx-hj110iz panel Optimized GOP timing and gamma.
Signed-off-by: Nyangcong <yangcong5@huaqin.corp-partner.google.com>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211201023230.344976-1-yangcong5@huaqin.corp-partner.google.com

Allow drm_fbdev_generic_setup() to pick the default bpp value for the
framebuffer.

This has no functional impact because the default is 32, given that
mode_config.preferred_depth is not set for Rockchip.
Suggested-by: NThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: NJohn Keeping <john@metanate.com>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20211101114622.813536-1-john@metanate.com

The Rockchip fbdev code does not add anything compared to
drm_fbdev_generic_setup(); the one custom function for .fb_mmap does the
same thing as gem_prime_mmap which is called by the helper.
Signed-off-by: NJohn Keeping <john@metanate.com>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20211029115014.264084-1-john@metanate.com

The aspeed driver uses the gem_cma_helper code, but does
noto enforce enabling this through Kconfig:

x86_64-linux-ld: drivers/gpu/drm/aspeed/aspeed_gfx_drv.o:(.rodata+0x2c8): undefined reference to `drm_gem_cma_prime_import_sg_table'
x86_64-linux-ld: drivers/gpu/drm/aspeed/aspeed_gfx_drv.o:(.rodata+0x2d8): undefined reference to `drm_gem_cma_dumb_create'
x86_64-linux-ld: drivers/gpu/drm/aspeed/aspeed_gfx_crtc.o: in function `aspeed_gfx_pipe_update':
aspeed_gfx_crtc.c:(.text+0xe5): undefined reference to `drm_fb_cma_get_gem_obj'

Add the same 'select' that is used in other such drivers.

Fixes: 09717af7 ("drm: Remove CONFIG_DRM_KMS_CMA_HELPER option")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20211204174637.1160725-2-arnd@kernel.org

The fsl-dcu driver uses the gem_cma_helper code, but does
noto enforce enabling this through Kconfig:

arm-linux-gnueabi-ld: drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.o:(.rodata+0x32c): undefined reference to `drm_gem_cma_prime_import_sg_table'
arm-linux-gnueabi-ld: drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.o:(.rodata+0x334): undefined reference to `drm_gem_cma_dumb_create'
arm-linux-gnueabi-ld: drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.o: in function `fsl_dcu_drm_plane_atomic_update':
fsl_dcu_drm_plane.c:(.text+0x144): undefined reference to `drm_fb_cma_get_gem_obj'

Add the same 'select' that is used in other such drivers.

Fixes: 09717af7 ("drm: Remove CONFIG_DRM_KMS_CMA_HELPER option")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20211204174637.1160725-1-arnd@kernel.org

GEM helper libraries use struct drm_driver.gem_create_object to let
drivers override GEM object allocation. On failure, the call returns
NULL.

Change the semantics to make the calls return a pointer-encoded error.
This aligns the callback with its callers. Fixes the ingenic driver,
which already returns an error pointer.

Also update the callers to handle the involved types more strictly.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NSteven Price <steven.price@arm.com>
Acked-by: NMaxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211130095255.26710-1-tzimmermann@suse.de

TTM takes full control over TTM_PL_SYSTEM placed buffers. This makes
driver internal usage of TTM_PL_SYSTEM prone to errors because it
requires the drivers to manually handle all interactions between TTM
which can swap out those buffers whenever it thinks it's the right
thing to do and driver.

CPU buffers which need to be fenced and shared with accelerators should
be placed in driver specific placements that can explicitly handle
CPU/accelerator buffer fencing.
Currently, apart, from things silently failing nothing is enforcing
that requirement which means that it's easy for drivers and new
developers to get this wrong. To avoid the confusion we can document
this requirement and clarify the solution.

This came up during a discussion on dri-devel:
https://lore.kernel.org/dri-devel/232f45e9-8748-1243-09bf-56763e6668b3@amd.comSigned-off-by: NZack Rusin <zackr@vmware.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211110145034.487512-1-zackr@vmware.com

There's never a need to access our internal kernel bo's from
user-space. Those objects are used exclusively for internal
support to guest backed surfaces (in otable setup and mob
page tables) and there's no need to have them be of device
type, i.e. mmappable from user-space.
Signed-off-by: NZack Rusin <zackr@vmware.com>
Reviewed-by: NMartin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-6-zackr@vmware.com

For larger (bigger than a page) and noncontiguous mobs we have
to create page tables that allow the host to find the memory.
Those page tables just used regular system memory. Unfortunately
in TTM those BO's are not allowed to be busy thus can't be
fenced and we have to fence those bo's  because we don't want
to destroy the page tables while the host is still executing
the command buffers which might be accessing them.

To solve it we introduce a new placement VMW_PL_SYSTEM which
is very similar to TTM_PL_SYSTEM except that it allows
fencing. This fixes kernel oops'es during unloading of the driver
(and pci hot remove/add) which were caused by busy BO's in
TTM_PL_SYSTEM being present in the delayed deletion list in
TTM (TTM_PL_SYSTEM manager is destroyed before the delayed
deletions are executed)
Signed-off-by: NZack Rusin <zackr@vmware.com>
Reviewed-by: NMartin Krastev <krastevm@vmware.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-5-zackr@vmware.com

Some of our hosts have a bug where rescaning a pci bus results in stale
fifo memory being mapped on the host. This makes any fifo communication
impossible resulting in various kernel crashes.

Instead of unexpectedly crashing, predictably fail to load the driver
which will preserve the system.

Fixes: fb1d9738 ("drm/vmwgfx: Add DRM driver for VMware Virtual GPU")
Signed-off-by: NZack Rusin <zackr@vmware.com>
Reviewed-by: NMartin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-4-zackr@vmware.com

The ttm mem global state was leaking if the vmwgfx driver load failed.

In case of a driver load failure we have to make sure we also release
the ttm mem global state.
Signed-off-by: NZack Rusin <zackr@vmware.com>
Reviewed-by: NMartin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-3-zackr@vmware.com

TTM during the transition to the new page allocator lost the ability
to constrain the allocations via the lower_mem_limit. The code has
been unused since the change:
256dd44b ("drm/ttm: nuke old page allocator")
and there's no reason to keep it.

Fixes: 256dd44b ("drm/ttm: nuke old page allocator")
Signed-off-by: NZack Rusin <zackr@vmware.com>
Reviewed-by: NMartin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105193845.258816-2-zackr@vmware.com

Calling dma_resv_add_excl_fence() with the fence as NULL and expecting
that that this frees up the fences is simply abuse of the internals of
the dma_resv object.

v2: drop the fence pruning completely.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129120659.1815-4-christian.koenig@amd.com

This is just abusing internals of the dma_resv object.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129120659.1815-3-christian.koenig@amd.com

The signaled bit is already used for quick testing if a fence is signaled.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/460722/Signed-off-by: NChristian König <christian.koenig@amd.com>

I'm not sure why it is useful to know the number of fences
in the reservation object, but we try to avoid exposing the
dma_resv_shared_list() function.

So use the iterator instead. If more information is desired
we could use dma_resv_describe() as well.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129120659.1815-5-christian.koenig@amd.com

It has been observed that with certain monitors such as the HP Z27n,
the register 0x825e reads a value of 0x79 when the HDMI cable is
connected and 0x78 when it is disconnected, i.e. bit 0 appears
to correspond to the HDMI connection status and bit 2 is never
set. Therefore, change the driver to check bit 0 instead of bit 2.
Signed-off-by: NPeter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I7e76411127e1ce4988a3f6d0c8ba5f1c3d880c23Reviewed-by: NVinod Koul <vkoul@kernel.org>
Signed-off-by: NRobert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117020724.2647769-1-pcc@google.com

Link drm_fb_cma_helper.o into drm_cma_helper.ko if CONFIG_DRM_KMS_HELPER
has been set. Remove CONFIG_DRM_KMS_CMA_HELPER config option. Selecting
KMS helpers and CMA will now automatically enable CMA KMS helpers.

Some drivers' Kconfig files did not correctly select KMS or CMA helpers.
Fix this as part of the change.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211106193509.17472-3-tzimmermann@suse.de

The MIPI DBI helpers access struct drm_gem_cma_object.vaddr in a
few places. Replace all instances with the correct generic GEM
functions. Use drm_gem_fb_vmap() for mapping a framebuffer's GEM
objects and drm_gem_fb_vunmap() for unmapping them. This removes
the dependency on CMA helpers within MIPI DBI.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211106193509.17472-2-tzimmermann@suse.de

Change all GEM CMA object functions that receive a GEM object
of type struct drm_gem_object to expect an object of type
struct drm_gem_cma_object instead.

This change reduces the number of upcasts from struct drm_gem_object
by moving them into callers. The C compiler can now verify that the
GEM CMA functions are called with the correct type.

For consistency, the patch also renames drm_gem_cma_free_object to
drm_gem_cma_free. It further updates documentation for a number of
functions.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NMaxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211115120148.21766-4-tzimmermann@suse.de

Wrap GEM CMA functions for struct drm_gem_object_funcs and update
all callers. This will allow for an update of the public interfaces
of the GEM CMA helper library.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NMaxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211115120148.21766-3-tzimmermann@suse.de

Restructure the header file for CMA helpers by moving declarations
for driver and file operations to the end of the file. No functional
changes.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NMaxime Ripard <maxime@cerno.tech>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211115120148.21766-2-tzimmermann@suse.de

The DRM hashtable code is only used by internal functions for legacy
UMS drivers. Move the implementation behind CONFIG_DRM_LEGACY and the
declarations into legacy header files. Unexport the symbols.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129094841.22499-4-tzimmermann@suse.de

Besides some legacy code, vmwgfx is the only user of DRM's hash-
table implementation. Copy the code into the driver, so that the
core code can be retired.

No functional changes. However, the real solution for vmwgfx is to
use Linux' generic hash-table functions.

v2:
	* add TODO item for updating vmwgfx (Sam)
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129094841.22499-3-tzimmermann@suse.de

Remove the include statement for drm_hashtab.h. It's not required
by TTM.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129094841.22499-2-tzimmermann@suse.de

Mark 'tidss_pm_ops' as __maybe_unused to avoid
the warning: unused variable 'tidss_pm_ops'

Fixes: 6e120594 ("drm/tidss: Make use of the helper macro SET_RUNTIME_PM_OPS()")
Signed-off-by: NCai Huoqing <caihuoqing@baidu.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211129063347.404-1-caihuoqing@baidu.com

The patch for commit 6a2d2ddf ("drm: Move nomodeset kernel parameter
to the DRM subsystem") was generated with config 'diff.noprefix true'.

But later was applied using 'cat nomodeset.mbox | dim apply-branch' on a
machine with 'diff.noprefix false'. And command 'git am --scissors -3' as
used by the dim tool doesn't handle that case well, since the 3-way merge
wrongly resolves the path for new file drivers/gpu/drm/drm_nomodeset.c as
gpu/drm/drm_nomodeset.c instead.

It led to the following build error as reported by the kernel test robot:

  make[4]: *** No rule to make target 'drivers/gpu/drm/drm_nomodeset.o', needed by 'drivers/gpu/drm/built-in.a'.

Fixes: 6a2d2ddf ("drm: Move nomodeset kernel parameter to the DRM subsystem")
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211127191910.709356-1-javierm@redhat.com

The message printed when nomodeset is present in the kernel command line
makes it look as if the parameter must never be used and it's a bad idea.

But there are valid reasons to use this parameter and the message should
not imply otherwise. Change the text to be more accurate and restrained.
Suggested-by: NThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Acked-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Acked-by: NPekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211112133230.1595307-7-javierm@redhat.com

The nomodeset kernel command line parameter is not documented. Its name
is quite vague and is not intuitive what's the behaviour when it is set.

Document in kernel-parameters.txt what actually happens when nomodeset
is used. That way, users could know if they want to enable this option.
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Acked-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Acked-by: NPekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211112133230.1595307-6-javierm@redhat.com

This relationship was only for historical reasons and the nomodeset option
should be available even on platforms that don't enable CONFIG_VGA_CONSOLE.
Suggested-by: NThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Acked-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Acked-by: NPekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211112133230.1595307-5-javierm@redhat.com