[why]
dc_stream_state containing a pointer to sink is poor design.
Sink describes the display, and the specifications or capabilities
it has.  That information is irrelevant for dc_stream_state, which describes
hardware state, and is generally used for hardware programming.  It
could further be argued that dc_sink itself is just a convenience dc
provides, and DC should be perfectly capable of programming hardware
without any dc_sinks (for example, emulated sinks).

[how]
Phase 1:
Deprecate use of dc_sink pointer in dc_stream.  Most references are trivial
to remove, but some call sites are risky (such as is_timing_changed) with
no obvious logical replacement.  These will be removed in follow up change.

Add dc_link pointer to dc_stream.  This is the typical reason DC really needed
sink pointer, and most call sites are replaced with this.

DMs also need minor updates, as all 3 DMs leverage stream->sink for
some functionality.  this is replaced instead by a pointer to private data
inside dc_stream_state, which is used by DMs as a quality of life improvment
for some key functionality.  it allows DMs to set pointers have to their own objects
which associate OS objects to dc_stream_states (such as DisplayTarget
and amdgpu_dm_connector).  Without the private pointer, DMs would be
forced to perform a lookup for callbacks.
Signed-off-by: NJun Lei <Jun.Lei@amd.com>
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NDavid Francis <David.Francis@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Resolves __udivdi3 missing errors when building for i386.

Fixes: 6378ef012ddc ("drm/amd/display: Add below the range support for FreeSync")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
When the flip-rate is below the minimum supported variable refresh rate
range for the monitor the front porch wait will timeout and be
frequently misaligned resulting in stuttering and/or flickering.

The FreeSync module can still maintain a smooth and flicker free
image when the monitor has a refresh rate range such that the maximum
refresh > 2 * minimum refresh by utilizing low framerate compensation,
"below the range".

[How]
Hook up the pre-flip and post-flip handlers from the FreeSync module.
These adjust the minimum/maximum vrr range to duplicate frames
when appropriate by tracking flip timestamps.
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
The behavior of drm_atomic_helper_cleanup_planes differs depending on
whether the commit was asynchronous or not. When it's called from
amdgpu_dm_atomic_commit_tail during a typical atomic commit the
plane state has been swapped so it calls cleanup_fb on the old plane
state.

However, in the asynchronous commit codepath the call to
drm_atomic_helper_commit also calls dm_plane_helper_cleanup_fb after
atomic_async_update has been called. Since the plane state is updated
in place and has not been swapped the cleanup_fb call affects the new
plane state.

This results in a use after free for the given sequence:

- Fast update, fb1 pin/ref, fb1 unpin/unref
- Fast update, fb2 pin/ref, fb2 unpin/unref
- Slow update, fb1 pin/ref, fb2 unpin/unref
- Fast update, fb2 pin/ref -> use after free. bug

[How]
Disallow framebuffer changes in the fast path. Since this includes
a NULL framebuffer, this means that only framebuffers that have
been previously pin+ref at least once will be used, preventing a
use after free.

This has a significant throughput reduction for cursor updates where
the framebuffer changes. For most desktop usage this isn't a problem,
but it does introduce performance regressions for two specific IGT
tests:

- cursor-vs-flip-toggle
- cursor-vs-flip-varying-size

Fixes: 2cc751931afc ("drm/amd/display: Add fast path for cursor plane updates")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Legacy cursor plane updates from drm helpers go through the full
atomic codepath. A high volume of cursor updates through this slow
code path can cause subsequent page-flips to skip vblank intervals
since each individual update is slow.

This problem is particularly noticeable for the compton compositor.

[How]
A fast path for cursor plane updates is added by using DRM asynchronous
commit support provided by async_check and async_update. These don't do
a full state/flip_done dependency stall and they don't block other
commit work.

However, DC still expects itself to be single-threaded for anything
that can issue register writes. Screen corruption or hangs can occur
if write sequences overlap. Every call that potentially perform
register writes needs to be guarded for asynchronous updates to work.
The dc_lock mutex was added for this.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106175Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by Leo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
These properties aren't being carried over when the atomic state.
This tricks atomic check and commit tail into performing underscan
and scaling operations when they aren't needed.

With the patch that forced scaling/RMX_ASPECT on by default this
results in many unnecessary surface updates and hangs under certain
conditions.

[How]
Duplicate the properties.

Fixes: 91b66c47 ("drm/amd/display: Set RMX_ASPECT as default")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
If the "max bpc" isn't explicitly set in the atomic state then it
have a value of 0. This has the correct behavior of limiting a panel
to 8bpc in the case where the panel supports 8bpc. In the case of eDP
panels this isn't a true assumption - there are panels that can only
do 6bpc.

Banding occurs for these displays.

[How]
Initialize the max_bpc when the connector resets to 8bpc. Also carry
over the value when the state is duplicated.

Bugzilla: https://bugs.freedesktop.org/108825
Fixes: 307638884f72 ("drm/amd/display: Support amdgpu "max bpc" connector property")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This reverts commit 91b66c47.

Forcing RMX_ASPECT as default uses the preferred/native mode's timings
for any mode the user selects and scales the image. This provides a
a consistently nicer result in the case where the selected mode's
refresh rate matches the native mode's refresh but this isn't always
the case.

For example, if the monitor is 1080p@144Hz and the preferred mode is
60Hz then even if the user selects 1080p@144Hz as their selected mode
they'll get 1080p@60Hz.
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Tracing is a useful and cheap debug functionality

[How]
This creates a new trace system amdgpu_dm, currently with
three trace events

amdgpu_dc_rreg and amdgpu_dc_wreg report the address and value
of any dc register reads and writes

amdgpu_dc_performance requires at least one of those two to be
enabled.  It counts the register reads and writes since the
last entry

v2: Don't check for NULL before kfree
Signed-off-by: NDavid Francis <David.Francis@amd.com>
Reviewed-by: NHarry Wentland <Harry.Wentland@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]

New GCC warnings for stringop-truncation and stringop-overflow help
catch common misuse of strncpy. This patch suppresses these warnings
by fixing bugs identified by them.

[How]

Since the parameter passed for name in amdpgu_dm_create_common_mode has
no fixed length, if the string is >= DRM_DISPLAY_MODE_LEN then
mode->name will not be null-terminated.

The truncation in fill_audio_info won't actually occur (and the string
will be null-terminated since the buffer is initialized to zero), but
the warning can be suppressed by using the proper buffer size.

This patch fixes both issues by using the real size for the buffer and
making use of strscpy (which always terminates).
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
When running igt@kms_plane@pixel-format-pipe-* tests the CRC read will
time out and the test will fail.

This is because the CRTC is duplicated but the crc_enabled parameter
isn't copied over to the new dm_crtc_state. CRC reads will time out
because amdgpu_dm_crtc_handle_crc_irq will no longer call
drm_crtc_add_crc_entry.

[How]
Copy crc_enabled when duplicating the state.
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NDavid Francis <David.Francis@amd.com>
Reviewed-by: NSun peng Li <Sunpeng.Li@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

* Use provided infopacket in stream (if valid) instead of reconstructing
  in set_vendor_info_packet()
* Use proper format for enums
* Use dc info packet struct instead
Signed-off-by: NHarmanprit Tatla <Harmanprit.Tatla@amd.com>
Reviewed-by: NAnthony Koo <Anthony.Koo@amd.com>
Acked-by: NKrunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
With scaling, underscan and abm changes we can end up calling
commit_planes_to_stream in commit_tail. This call uses dm_state->context
which can be NULL if the commit was a fast update.

[How]
Use dc_state instead since that can't be NULL unless the system ran
out of memory.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108912
Fixes: e64abff2f133 ("drm/amd/display: Use private obj helpers for dm_atomic_state")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Calculate preferred refresh rate only when preferred mode exists.
Signed-off-by: NJerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>
Reviewed-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
If the "max bpc" isn't explicitly set in the atomic state then it
have a value of 0. This has the correct behavior of limiting a panel
to 8bpc in the case where the panel supports 8bpc. In the case of eDP
panels this isn't a true assumption - there are panels that can only
do 6bpc.

Banding occurs for these displays.

[How]
Initialize the max_bpc when the connector resets to 8bpc. Also carry
over the value when the state is duplicated.

Bugzilla: https://bugs.freedesktop.org/108825
Fixes: 307638884f72 ("drm/amd/display: Support amdgpu "max bpc" connector property")
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Support for AMDGPU specific FreeSync properties and ioctls are dropped
from amdgpu_dm in favor of supporting drm variable refresh rate
properties.

The notify_freesync and set_freesync_property functions are dropped
from amdgpu_display_funcs.

The drm vrr_capable property is now attached to any DP/HDMI connector.
Its value is updated accordingly to the connector's FreeSync capabiltiy.

The freesync_enable logic and ioctl control has has been dropped in
favor of utilizing the vrr_enabled on the drm CRTC. This allows for more
fine grained atomic control over which CRTCs should support variable
refresh rate.

To handle state changes for vrr_enabled it was easiest to drop the
forced modeset on freesync_enabled change. This patch now performs the
required stream updates when planes are flipped.

This is done for a few reasons:

(1) VRR stream updates can be done in the fast update path

(2) amdgpu_dm_atomic_check would need to be hacked apart to check
    desired variable refresh state and capability before the CRTC
    disable pass.

(3) Performing VRR stream updates on-flip is needed for enabling BTR
    support.

VRR packets and timing adjustments are now tracked and compared to
previous values sent to the hardware.
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

The fallback code for getting default backlight caps was using
the wrong variable name.  Fix it.

Fixes: https://lists.freedesktop.org/archives/dri-devel/2018-November/197752.htmlSigned-off-by: NDavid Francis <David.Francis@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Two non-blocking commits in succession can result in a sequence where
the same dc->current_state is queried for both commits.

1. 1st commit -> check -> commit -> swaps atomic state -> queues work
2. 2nd commit -> check -> commit -> swaps atomic state -> queues work
3. 1st commit work finishes

The issue with this sequence is that the same dc->current_state is
read in both atomic checks. If the first commit modifies streams or
planes those will be missing from the dc->current_state for the
second atomic check. This result in many stream and plane errors in
atomic commit tail.

[How]
The driver still needs to track old to new state to determine if the
commit in its current implementation. Updating the dc_state in
atomic tail is wrong since the dc_state swap should be happening as
part of drm_atomic_helper_swap_state *before* the worker queue kicks
its work off.

The simplest replacement for the subclassing (which doesn't properly
manage the old to new atomic state swap) is to use the drm private
object helpers. While some of the dc_state members could be merged
into dm_crtc_state or dm_plane_state and copied over that way it is
easier for now to just treat the whole dc_state structure as a single
private object.

This allows amdgpu_dm to drop the dc->current_state copy from within
atomic check. It's replaced by a copy from the current atomic state
which is propagated correctly for the sequence described above.

Since access to the dm_state private object is now locked this should
also fix issues that could arise if submitting non-blocking commits
from different threads.

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

ACPI ATIF has a function called query
backlight transfer characteristics.  Among the
information returned by this function is
the minimum and maximum input signals for the
backlight

Call that function on ACPI init.  When DM
backlight device is updated, copy over the
backlight caps into DM, but only once.  Use
the backlight caps in the backlight-to-dc
calculation
Signed-off-by: NDavid Francis <David.Francis@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Adaptive Backlight Management (ABM) is a feature
that reduces backlight level to save power, while
increasing pixel contrast and pixel luminance
to maintain readability and image quality.

ABM will adjust in response to the
pixel luminance of the displayed content.

ABM is made available as a drm property on eDP
monitors called "abm level", which ranges from 0 to 4.
When this property is set to 0, ABM is off.  Levels 1
to 4 represent different ranges of backlight reduction.
At higher levels both the backlight reduction and pixel
adjustment will be greater.

ABM requires DMCU firmware, which is currently available for
Raven ASICs only.  If the feature does not work, please
ensure your firmware is up to date.

v2:
Fix commit message, only attach property if DMCU loaded
v3:
Store ABM level in crtc state to accommodate dc
v4:
Fix ABM saving on dpms cycle
Signed-off-by: NDavid Francis <David.Francis@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

DMCU IRAM must be loaded by the driver before DMCU
can function.

Move the IRAM code out of the shadows and into a new file
modules/power/power_helpers.c

The IRAM table contains the backlight curve and ABM parameters

Add this new file to the Makefiles

Call dmcu_load_iram in late init of DM

Move struct dmcu_version from dc.h to dmcu.h to allow
dmcu to be included on its own
Signed-off-by: NDavid Francis <David.Francis@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Before:
We use drm_match_cea_mode() to get the vic for any mode we
want to set, most of the time vic will be different for the new mode.

DC uses memcmp to check if timing changed, in this case DC will
say timing changed and we endup doing a full modeset.

Current:
Now we check if !RMX_OFF and old_refresh == new_refresh if so
we copy the vic from old timing. In a case where we are currently on
a lower timing and want to change to higher mode, stream->dst will be
different and cause us to do a full modeset, which is what we want.
Signed-off-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Setting this allows for display scaling by default
Signed-off-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Remove dm_services_types.h which is included more than once
Signed-off-by: NBrajeswar Ghosh <brajeswar.linux@gmail.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Many panels support more than 8bpc but some modes are unavailable while
running at greater than 8bpc due to DP/HDMI bandwidth constraints.

Support for more than 8bpc was added recently in the driver but it
defaults to the maximum supported bpc - locking out these modes.

This should be a user configurable option such that the user can select
what bpc configuration they would like.

[How]
This patch adds support for getting and setting the amdgpu driver
specific "max bpc" property on the connector.

It also adds support for limiting the output bpc based on the property
value. The default limitation is the lowest value in the range, 8bpc.
This was the old value before the range was uncapped.

This patch should be updated/replaced later once common drm support
for max bpc lands.

Bugzilla: https://bugs.freedesktop.org/108542
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201585
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200645
Fixes: e03fd3f3 ("drm/amd/display: Do not limit color depth to 8bpc")

v2: rebase on upstream (Alex)
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Many panels support more than 8bpc but some modes are unavailable while
running at greater than 8bpc due to DP/HDMI bandwidth constraints.

Support for more than 8bpc was added recently in the driver but it
defaults to the maximum supported bpc - locking out these modes.

This should be a user configurable option such that the user can select
what bpc configuration they would like.

[How]
This patch adds support for getting and setting the amdgpu driver
specific "max bpc" property on the connector.

It also adds support for limiting the output bpc based on the property
value. The default limitation is the lowest value in the range, 8bpc.
This was the old value before the range was uncapped.

This patch should be updated/replaced later once common drm support
for max bpc lands.

Bugzilla: https://bugs.freedesktop.org/108542
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201585
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200645
Fixes: e03fd3f3 ("drm/amd/display: Do not limit color depth to 8bpc")

v2: rebase on upstream (Alex)
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
It is not correct to touch aconnector within atomic_check.

[How]
It was added as workaround before, and no longer needed.
Signed-off-by: NJerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Set the dc_config properly when the option is enabled.
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
It is not correct to touch aconnector within atomic_check.

[How]
It was added as workaround before, and no longer needed.
Signed-off-by: NJerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Set the dc_config properly when the option is enabled.
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
drm_plane_cleanup does not free the plane.

[How]
Call drm_primary_helper_destroy which will also free the plane.
Signed-off-by: NHarry Wentland <harry.wentland@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This reverts commit 0cafc82f.

This breaks some apps that assume 0 is minimum brightness.

Revert for 4.20.  This is fixed properly for drm-next/4.21 in:
"drm/amd: Don't fail on backlight = 0"
However, that patch depends on more extensive changes to the
backlight interface which are too invasive for -fixes.

Fixes: Bugzilla: https://bugs.freedesktop.org/108668Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
drm_plane_cleanup does not free the plane.

[How]
Call drm_primary_helper_destroy which will also free the plane.
Signed-off-by: NHarry Wentland <harry.wentland@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

It's unnecessarily duplicating drm_plane_type.
Signed-off-by: NHarry Wentland <harry.wentland@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Amgpu's backlight update status function was
returning 1 (an error value) when the backlight
property was 0.  This breaks users that assume
0 is a valid backlight value (which is a
correct assumption)

If the user passes in a backlight value of 0,
tell them everything is fine, then write a value of
1 to hardware.
Signed-off-by: NDavid Francis <David.Francis@amd.com>
Bugzilla: https://bugs.freedesktop.org/108668
Fixes: 416615ea9578 ("drm/amd/display: set backlight level limit to 1")
Cc: Suresh.Guttula@amd.com
Cc: Harry.Wentland@amd.com
Cc: Samantham@posteo.net
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why] We want to increase precision for backlight setting.
But DC interface takes 8 bit backlight level value only.

[How] DMCU already takes 16 bit backlight level.
Expand the DC interface to take 16.16 bit value.
Max 32 bit backlight value (0xFFFF) will represent
max backlight (100%)
Signed-off-by: NAnthony Koo <Anthony.Koo@amd.com>
Reviewed-by: NTony Cheng <Tony.Cheng@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Documentation is helpful for the community to understand our code.
This change does some high-level documentation of some DM interfaces
with DRM, and the amdgpu base driver.

[How]
An entry for AMDgpu DC has been added to Documentation/gpu/drivers.rst
TOC. amdgpu-dc.rst is created to pull in inline doc-strings, which:
- Provides an overview for "What is DM?"
- Documents AMDgpu DM lifecyle
- Documents IRQ management
- Documents atomic_check and commit_tail interfaces
Signed-off-by: NLeo Li <sunpeng.li@amd.com>
Reviewed-by: NDavid Francis <David.Francis@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Fix surface/plane potential nullptr

[How]
add null check
Signed-off-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Need separate feature flag for DP 4:2:0 support, since existing
flag is used for HDMI

[How]
Added dp_ycbcr420_supported to struct encoder_feature_support
Signed-off-by: NEric Bernstein <eric.bernstein@amd.com>
Reviewed-by: NTony Cheng <Tony.Cheng@amd.com>
Acked-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

This patch will work as workaround for silicon limitation
related to PWM dutycycle when the backlight level goes to 0.

Actually PWM value is 16 bit value and valid range from 1-65535.
when ever user requested to set this PWM value to 0 which is not
fall in the range, in VBIOS taken care this by limiting to 1.
This patch here will do the same. Either driver or VBIOS can not
pass 0 value as it is not a valid range for PWM and it will
give a high PWM pulse which is not the intended behaviour as
per HW constraints.
Signed-off-by: Nsuresh guttula <suresh.guttula@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>