Properly protect the relevant code with CONFIG_DRM_AMD_DC_DCN.

Fixes: 0b08c54b ("drm/amd/display: Fix the display corruption issue on Navi10")
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
There is a DRM_ERROR when the dc_sink is NULL and
there should not be this warning when the connector
is forced.

[how]
Do not warn if dc_sink is NULL if the connector
is forced.
Signed-off-by: NVictor Lu <victorchengchi.lu@amd.com>
Reviewed-by: NNicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: NQingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
We want to trigger atomic check on connector when
DSC debugfs properties are changed. The previous
method was reverted because it accessed connector
properties unsafely and would also heavily
impact performance.

[How]
Add a flag for forcing DSC update in CRTC state
and add connector to the state if the flag is set.
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Reviewed-by: NNicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: NQingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

We're unconditionally using modifiers internally for GFX9+ now.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This expose modifier support on GFX9+.

Only modifiers that can be rendered on the current GPU are
added. This is to reduce the number of modifiers exposed.

The HW could expose more, but the best mechanism to decide
what to expose without an explosion in modifiers is still
to be decided, and in the meantime this should not regress
things from pre-modifiers and does not risk regressions as
we make up our mind in the future.

v2:
  - Added comment that D on Raven is only valid for 64bpp
    and will be filtered based on format later.
  - Removed D tiling modes that weren't useful for 64bpp
    on GFX10+.

v4: Add AMDGPU_FAMILY_VGH case.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

For DCC we will use 2/3 planes to avoid X rendering to the frontbuffer
with DCC compressed images. To make this work with the core KMS
validation we need to add extra formats with the extra planes.

However, due to flexibility we set bpp = 0 for the extra planes and
do the validation ourselves.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This sets the DC tiling options from the modifier, if modifiers
are used for the FB. This patch by itself does not expose the
support yet though.

There is not much validation yet to limit the scope of this
patch, but the current validation is at the same level as
the BO metadata path.

v2: Add modifier check to should_reset_plane.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Prepare for inserting modifiers based configuration, while sharing
a bunch of DCC validation & initializing the device-based configuration.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This moves the tiling_flags to the framebuffer creation.
This way the time of the "tiling" decision is the same as it
would be with modifiers.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

With modifiers I'd like to support non-dedicated buffers for
images.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Cc: stable@vger.kernel.org # 5.1.0
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Silently accepting it could result in corruption.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

No need for a separate config option at this point.
Reviewed-by: NLuben Tuikov <luben.tuikov@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Debug amdgpu_dm could be a complicated task, therefore, this commit adds
tracepoints in some convenient functions such as plane and connector
check inside amdgpu_dm.
Signed-off-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Our DC currently uses some of the tracepoint function inside a DC
header, which means that many other files implicitly include part of the
trace function. This situation limits how we can expand this feature for
other parts of the driver by generating multiple compilation errors when
we try to reuse some of the existing structures. This commit decouples
part of the amdgpu_dm_trace from DC core to simplify the trace
enlargement in future changes.
Signed-off-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why] Can be used for debug purposes
[How] Add max target bpp override field and related handling
Signed-off-by: NNikola Cornij <nikola.cornij@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This reverts commit c44a22b3.

Reason for revert: Patch introduces performance issues and might
cause memory consistency problems with multiple connectors.
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

	dm_comressor_info -> dm_compressor_info

The kernel-doc markup is right, but the struct itself
and their references contain a typo.
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Screen corruption on Navi10 card

[How]
Set system context in DCN only on Renoir
Tested-by: NMatt Coffin <mcoffin13@gmail.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NYifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: NRoman Li <Roman.Li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

As far a I can tell uses a variant of DCN3xx which uses num_pkrs.

If we do not initialize the variable we will set the register field
to ilog2(0) = -1, though the mask will reduce that to 7. Pretty sure
7 is not the value we want here.
Signed-off-by: NBas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: NMarek Olšák <marek.olsak@amd.com>
Reviewed-and-Tested-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

On connector destruction call drm_dp_mst_topology_mgr_destroy
to release resources allocated in drm_dp_mst_topology_mgr_init.
Do it only if MST manager was initilized before otherwsie a crash
is seen on driver unload/device unplug.
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This fixes regression on device unplug and/or driver unload.

[   65.681501 <    0.000004>] BUG: kernel NULL pointer dereference, address: 0000000000000008
[   65.681504 <    0.000003>] #PF: supervisor write access in kernel mode
[   65.681506 <    0.000002>] #PF: error_code(0x0002) - not-present page
[   65.681507 <    0.000001>] PGD 7c9437067 P4D 7c9437067 PUD 7c9db7067 PMD 0
[   65.681511 <    0.000004>] Oops: 0002 [#1] SMP NOPTI
[   65.681512 <    0.000001>] CPU: 8 PID: 127 Comm: kworker/8:1 Tainted: G        W  O      5.9.0-rc2-dev+ #59
[   65.681514 <    0.000002>] Hardware name: System manufacturer System Product Name/PRIME X470-PRO, BIOS 4406 02/28/2019
[   65.681525 <    0.000011>] Workqueue: events drm_connector_free_work_fn [drm]
[   65.681535 <    0.000010>] RIP: 0010:drm_atomic_private_obj_fini+0x11/0x60 [drm]
[   65.681537 <    0.000002>] Code: de 4c 89 e7 e8 70 f2 ba f8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 90 0f 1f 44 00 00 48 8b 47 08 48 8b 17 55 48 89 e5 53 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 fb 48 89
[   65.681541 <    0.000004>] RSP: 0018:ffffa5fa805efdd8 EFLAGS: 00010246
[   65.681542 <    0.000001>] RAX: 0000000000000000 RBX: ffff9a4b094654d8 RCX: 0000000000000000
[   65.681544 <    0.000002>] RDX: 0000000000000000 RSI: ffffffffba197bc2 RDI: ffff9a4b094654d8
[   65.681545 <    0.000001>] RBP: ffffa5fa805efde0 R08: ffffffffba197b82 R09: 0000000000000040
[   65.681547 <    0.000002>] R10: ffffa5fa805efdc8 R11: 000000000000007f R12: ffff9a4b09465888
[   65.681549 <    0.000002>] R13: ffff9a4b36f20010 R14: ffff9a4b36f20290 R15: ffff9a4b3a692840
[   65.681551 <    0.000002>] FS:  0000000000000000(0000) GS:ffff9a4b3ea00000(0000) knlGS:0000000000000000
[   65.681553 <    0.000002>] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   65.681554 <    0.000001>] CR2: 0000000000000008 CR3: 00000007c9c82000 CR4: 00000000003506e0
[   65.681556 <    0.000002>] Call Trace:
[   65.681561 <    0.000005>]  drm_dp_mst_topology_mgr_destroy+0xc4/0xe0 [drm_kms_helper]
[   65.681612 <    0.000051>]  amdgpu_dm_connector_destroy+0x3d/0x110 [amdgpu]
[   65.681622 <    0.000010>]  drm_connector_free_work_fn+0x78/0x90 [drm]
[   65.681624 <    0.000002>]  process_one_work+0x164/0x410
[   65.681626 <    0.000002>]  worker_thread+0x4d/0x450
[   65.681628 <    0.000002>]  ? rescuer_thread+0x390/0x390
[   65.681630 <    0.000002>]  kthread+0x10a/0x140
[   65.681632 <    0.000002>]  ? kthread_unpark+0x70/0x70
[   65.681634 <    0.000002>]  ret_from_fork+0x22/0x30

This reverts commit 1545fbf9.
Signed-off-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
display S/G mode fails in Renoir

[how]
Setup system context in dm init.
Signed-off-by: NYifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Display Manager support for green_sardine
Signed-off-by: NRoman Li <Roman.Li@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Handle CAVE_DIMGREY_CAVEFISH in amdgpu_dm

v2: fix rebase typo (Alex)
Signed-off-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Update dm for vangogh support.
Signed-off-by: NRoman Li <Roman.Li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Don't check drm_crtc_state::active for this either, per its
documentation in include/drm/drm_crtc.h:

 * Hence drivers must not consult @active in their various
 * &drm_mode_config_funcs.atomic_check callback to reject an atomic
 * commit.

atomic_remove_fb disables the CRTC as needed for disabling the primary
plane.

This prevents at least the following problems if the primary plane gets
disabled (e.g. due to destroying the FB assigned to the primary plane,
as happens e.g. with mutter in Wayland mode):

* The legacy cursor ioctl returned EINVAL for a non-0 cursor FB ID
  (which enables the cursor plane).
* If the cursor plane was enabled, changing the legacy DPMS property
  value from off to on returned EINVAL.

v2:
* Minor changes to code comment and commit log, per review feedback.

GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1108
GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1165
GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1344Suggested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NMichel Dänzer <mdaenzer@redhat.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
We want to trigger atomic check on connector, which DSC debugfs
properties have changed.

[how]
Add a helper function that iterates through all active connectors
and add them to the state if DSC debugfs parameters have changed.
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NMikita Lipski <mikita.lipski@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
When comparing current DSC timing settings with enforced through
debugfs we have to calculate number of both vertical and horisontal
slices. So instead of doing that every time we should just
use number of slices rather than setting its dimensions.

[how]
In connector's dsc preferred settings structure change slice height
and slice width parameters to number of slices vertical and horisontal.
Also calculate number of slices in debugfs rather in create_stream_for_sink.
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NMikita Lipski <mikita.lipski@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
For debug purposes we want not to enable DSC on certain connectors
even if algorithm deesires to do so, instead it should enable DSC
on other capable connectors or fail the atomic check.

[how]
Adding the third option to connector's debugfs entry dsc_clock_en.

Accepted inputs:
     0x0 - connector is using default DSC enablement policy
     0x1 - force enable DSC on the connector, if it supports DSC
     0x2 - force disable DSC on the connector, if DSC is supported

Ex. # echo 0x2 > /sys/kernel/debug/dri/0/DP-1/dsc_clock_en
Signed-off-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NMikita Lipski <mikita.lipski@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
ABM feature initialization was not executed due to early return.

dm_late_init() had an early return in case if DMCU is not used.
With the implementation of ABM on DMUB, DMCU can be disabled
but ABM still needs to be initialized.

[How]
Remove verification for DMCU from the top of the function.
The existing logic will handle the case when DMCU is not used.
Signed-off-by: NRoman Li <roman.li@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Disable triplebuffering by default.
Signed-off-by: NAric Cyr <aric.cyr@amd.com>
Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why&How]
Since there is no need for accessing crtc state in the interrupt
handler, interrupts need not be disabled well in advance, and
can be moved to commit_tail where it should be.
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why&How]
Currently commit_tail holds global locks and wait for dependencies which is
against the DRM API contracts. Inorder to fix this, IRQ handler should be able
to run without having to access crtc state. Required parameters are copied over
so that they can be directly accessed from the interrupt handler
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why&How]
To refactor DM IRQ management, all fields used by IRQ is best moved
to a separate struct so that main amdgpu_crtc struct need not be changed
Location of the new struct shall be in DM
Reviewed-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: NAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Remove the private obj from the internal list before we free aconnector.

[   56.925828] BUG: unable to handle page fault for address: ffff8f84a870a560
[   56.933272] #PF: supervisor read access in kernel mode
[   56.938801] #PF: error_code(0x0000) - not-present page
[   56.944376] PGD 18e605067 P4D 18e605067 PUD 86a614067 PMD 86a4d0067 PTE 800ffff8578f5060
[   56.953260] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI
[   56.958815] CPU: 6 PID: 1407 Comm: bash Tainted: G           O      5.9.0-rc2+ #46
[   56.967092] Hardware name: System manufacturer System Product Name/PRIME Z390-A, BIOS 1401 11/26/2019
[   56.977162] RIP: 0010:__list_del_entry_valid+0x31/0xa0
[   56.982768] Code: 00 ad de 55 48 8b 17 4c 8b 47 08 48 89 e5 48 39 c2 74 27 48 b8 22 01 00 00 00 00 ad de 49 39 c0 74 2d 49 8b 30 48 39 fe 75 3d <48> 8b 52 08 48 39 f2 75 4c b8 01 00 00 00 5d c3 48 89 7
[   57.003327] RSP: 0018:ffffb40c81687c90 EFLAGS: 00010246
[   57.009048] RAX: dead000000000122 RBX: ffff8f84ea41f4f0 RCX: 0000000000000006
[   57.016871] RDX: ffff8f84a870a558 RSI: ffff8f84ea41f4f0 RDI: ffff8f84ea41f4f0
[   57.024672] RBP: ffffb40c81687c90 R08: ffff8f84ea400998 R09: 0000000000000001
[   57.032490] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000006
[   57.040287] R13: ffff8f84ea422a90 R14: ffff8f84b4129a20 R15: fffffffffffffff2
[   57.048105] FS:  00007f550d885740(0000) GS:ffff8f8509600000(0000) knlGS:0000000000000000
[   57.056979] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   57.063260] CR2: ffff8f84a870a560 CR3: 00000007e5144001 CR4: 00000000003706e0
[   57.071053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   57.078849] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   57.086684] Call Trace:
[   57.089381]  drm_atomic_private_obj_fini+0x29/0x82 [drm]
[   57.095247]  amdgpu_dm_fini+0x83/0x170 [amdgpu]
[   57.100264]  dm_hw_fini+0x23/0x30 [amdgpu]
[   57.104814]  amdgpu_device_fini+0x1df/0x4fe [amdgpu]
[   57.110271]  amdgpu_driver_unload_kms+0x43/0x70 [amdgpu]
[   57.116136]  amdgpu_pci_remove+0x3b/0x60 [amdgpu]
[   57.121291]  pci_device_remove+0x3e/0xb0
[   57.125583]  device_release_driver_internal+0xff/0x1d0
[   57.131223]  device_release_driver+0x12/0x20
[   57.135903]  pci_stop_bus_device+0x70/0xa0
[   57.140401]  pci_stop_and_remove_bus_device_locked+0x1b/0x30
[   57.146571]  remove_store+0x7b/0x90
[   57.150429]  dev_attr_store+0x17/0x30
[   57.154441]  sysfs_kf_write+0x4b/0x60
[   57.158479]  kernfs_fop_write+0xe8/0x1d0
[   57.162788]  vfs_write+0xf5/0x230
[   57.166426]  ksys_write+0x70/0xf0
[   57.170087]  __x64_sys_write+0x1a/0x20
[   57.174219]  do_syscall_64+0x38/0x90
[   57.178145]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Nxinhui pan <xinhui.pan@amd.com>
Acked-by: Feifei Xu <Feifei Xu@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

When amdgpu_display_modeset_create_props() fails, state and
state->context should be freed to prevent memleak. It's the
same when amdgpu_dm_audio_init() fails.
Signed-off-by: NDinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Current function excludes the logic to generate H14b-VSIF. Now it
constructs HF-VSIF only and causes HDMI compliace test fail.

[How]
According to HDMI spec, source devices shall utilize the H14b-VSIF
whenever the signaling capabilities of the H14b-VSIF allow this.

Here keep the logic for HF-VSIF and add H14b-VSIF construction part.
Signed-off-by: NWayne Lin <Wayne.Lin@amd.com>
Reviewed-by: NRoman Li <Roman.Li@amd.com>
Acked-by: NEryk Brol <eryk.brol@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

When amdgpu_display_modeset_create_props() fails, state and
state->context should be freed to prevent memleak. It's the
same when amdgpu_dm_audio_init() fails.
Signed-off-by: NDinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers: gpu: amd: Initialize amdgpu_dm_backlight_caps object to 0 in amdgpu_dm_update_backlight_caps

In `amdgpu_dm_update_backlight_caps()`, there is a local
`amdgpu_dm_backlight_caps` object that is filled in by
`amdgpu_acpi_get_backlight_caps()`. However, this object is
uninitialized before the call and hence the subsequent check for
aux_support can fail since it is not initialized by
`amdgpu_acpi_get_backlight_caps()` as well. This change initializes
this local `amdgpu_dm_backlight_caps` object to 0.
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NFurquan Shaikh <furquan@google.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Documentation for sysfs backlight level interface requires that
values in both 'brightness' and 'actual_brightness' files are
interpreted to be in range from 0 to the value given in the
'max_brightness' file.

With amdgpu, max_brightness gives 255, and values written by the user
into 'brightness' are internally rescaled to a wider range. However,
reading from 'actual_brightness' gives the raw register value without
inverse rescaling. This causes issues for various userspace tools such
as PowerTop and systemd that expect the value to be in the correct
range.

Introduce a helper to retrieve internal backlight range. Use it to
reimplement 'convert_brightness' as 'convert_brightness_from_user' and
introduce 'convert_brightness_to_user'.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=203905
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1242
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlexander Monakov <amonakov@ispras.ru>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org