[Why]
The issue only occurs during the GPU reset code path.

We first backup the current state prior to commiting 0 streams
internally from DM to DC. This state backup contains valid link
encoder assignments.

DC will clear the link encoder assignments as part of current state
(but not the backup, since it was a copied before the commit) and
free the extra stream reference it held.

DC requires that the link encoder assignments remain cleared/invalid
prior to commiting. Since the backup still has valid assignments we
call the interface post reset to clear them. This routine also
releases the extra reference that the link encoder interface held -
resulting in a double free (and eventually a NULL pointer dereference).

[How]
We'll have to do a full DC commit anyway after GPU reset because
the stream count previously went to 0.

We don't need to retain the assignment that we had backed up, so
just copy off of the now clean current state assignment after the
reset has occcurred with the new link_enc_cfg_copy() interface.

Fixes: 6d63fcc2 ("drm/amd/display: Reset link encoder assignments for GPU reset")
Reviewed-by: NJimmy Kizito <Jimmy.Kizito@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Virtualization enters blue screen of death (BSoD)
due to NULL res_pool object when accessing DSC
encoder capability.

[How]
Add NULL check to avoid blue screen of death.
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NChris Park <Chris.Park@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drm/amd/display: 3.2.176

    This version brings along following fixes:
    - move FPU operations from dcn21 to dml/dcn20 folder
    - move FPU-related code from dcn20 to dml folder
    - Fix compile error from TO_CLK_MGR_INTERNAL
    - Fix double free during GPU reset on DC streams
    - Add NULL check
    - [FW Promotion] Release 0.0.107.0
    - enable dcn315/316 s0i2 support
    - handle DP2.0 RX with UHBR20 but not UHBR13.5 support
    - disable HPD SW timer for passive dongle type 1 only
    - add gamut coefficient set A and B
    - merge two duplicated clock_source_create
    - Add link dp trace support
    - move FPU associated DCN303 code to DML folder
    - Release AUX engine after failed acquire
    - Add minimal pipe split transition state
    - Clean up fixed VS PHY test w/a function
    - fix the clock source contruct for dcn315
    - cleaning up smu_if to add future flexibility
    - fix deep color ratio
    - add debug option to bypass ssinfo from bios for dcn315
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NAric Cyr <aric.cyr@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NAnthony Koo <Anthony.Koo@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
enable the support in driver, let the control by CMOS
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NCharlene Liu <Charlene.Liu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
DP2.0 defines DP2.0 RX capability using bit maps. This means there is
a corner case the DP2.0 RX can declare UHBR20 capability but not UHBR13.5 support.
In this case we should skip UHBR13.5 selection and continue to our next option
in decide liink settings.
Reviewed-by: NGeorge Shen <George.Shen@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NWenjing Liu <wenjing.liu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
Need to provide this workaround
only for type 1 passive dongle

[how]
Detect if dongle is type 1 or 2.
And use it to determine if w/a is needed.
Reviewed-by: NCharlene Liu <Charlene.Liu@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NSung Joon Kim <sungjoon.kim@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Screen shake on DCN3 night light SDR BR3.

[How]
Change the logic to use double buffer reisgter on gamut settings.
Reviewed-by: NKrunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NJingwen Zhu <jingwen.zhu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
dcn31x could use dcn31 sepcific which contains deep_color_ratio for dmub
Reviewed-by: NNevenko Stupar <Nevenko.Stupar@amd.com>
Reviewed-by: NHansen Dsouza <hansen.dsouza@amd.com>
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NCharlene Liu <Charlene.Liu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
It is nice to have link training and link loss status logging in
our trace, and this patch add the all necessary accessors in dc
side.

[How]
1. Define dp_trace struct and create new file link_dp_trace.c and
link_dp_trace.h;
2. Add dp link training status update in dc_link_dp.c;
Reviewed-by: NWenjing Liu <Wenjing.Liu@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NLeo (Hanghong) Ma <hanghong.ma@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why & How]
As part of the FPU isolation work documented in
https://patchwork.freedesktop.org/series/93042/, isolate
code that uses FPU in DCN303 to DML, where all FPU code
should locate.
Co-authored-by: NJasdeep Dhillon <jasdeep.dhillon@amd.com>
Reviewed-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NJasdeep Dhillon <jasdeep.dhillon@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
There is a sequence in which aux arbitration
doesn't work correctly. Driver is left with
aux access after it times out waiting for access.
In future dmub fw is never granted aux access
and is stuck in a while loop.

[How]
Cancel aux request from driver after timing out.
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NWyatt Wood <wyatt.wood@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[WHY?] When adding/removng a plane to some configurations,
unsupported pipe programming can occur when moving to a new plane.

[HOW?]
Add a safe transistion state before programming new configuration.
Reviewed-by: NAric Cyr <Aric.Cyr@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NDillon Varone <dillon.varone@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why]
Unify naming for fixed VS workarounds.

[How]
Rename function to match naming convention.
Refactor code to remove unused function.
Reviewed-by: NWenjing Liu <Wenjing.Liu@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NGeorge Shen <george.shen@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[why]
Driver sends invalid deep color ratio to DMUB. Update it to the right
one by using another clock source construct.
Reviewed-by: NHansen Dsouza <hansen.dsouza@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NCharlene Liu <charlene.liu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

why and how:
need to hook in new smu interfaces
cleaning up code that used old variables
Reviewed-by: NNevenko Stupar <Nevenko.Stupar@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NLeung, Martin <Martin.Leung@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Fix enum mapping for deep color ratio
Reviewed-by: NCharlene Liu <Charlene.Liu@amd.com>
Acked-by: NAlan Liu <HaoPing.Liu@amd.com>
Signed-off-by: NHansen Dsouza <Hansen.Dsouza@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

[Why & How]
Add debug option to bypass ssinfo from BIOS for dcn315.
Reviewed-by: NPark, Chris <Chris.Park@amd.com>
Acked-by: NQingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: NCharlene Liu <Charlene.Liu@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

smu 13.0.5 use new registers for smu msg and param.
Signed-off-by: NYifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

On aldebaran, BACO dummy mode may be enabled during reset. Disable
it during resume.
Signed-off-by: NLijo Lazar <lijo.lazar@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Merge tag 'drm-intel-next-fixes-2022-03-10' of git://anongit.freedesktop.org/drm/drm-intel into drm-next

- Reduce overzealous alignment constraints for GGTT
- Add missing mdev attribute "name" for GVT
- Async flip fixes (Ville)
- Static checker fix (Ville)
Signed-off-by: NDave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YimvoLOZ8RPKrITv@jlahtine-mobl.ger.corp.intel.com

Merge tag 'amd-drm-next-5.18-2022-03-09' of https://gitlab.freedesktop.org/agd5f/linux into drm-next

amd-drm-next-5.18-2022-03-09:

amdgpu:
- Misc code cleanups
- Misc display fixes
- PSR display fixes
- More RAS cleanup
- Hotplug fix
- Bump minor version for hotplug tests
- SR-IOV fixes
- GC 10.3.7 updates
- Remove some firmwares which are no longer used
- Mode2 reset refactor
- Aldebaran fixes
- Add VCN fwlog feature for VCN debugging
- CS code cleanup
- Fix clang warning
- Fix CS clean up rebase breakage

amdkfd:
- SVM fixes
- SMI event fixes and cleanups
- vmid_pasid mapping fix for gfx10.3
Signed-off-by: NDave Airlie <airlied@redhat.com>
From: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220309224439.2178877-1-alexander.deucher@amd.com

Follow-up pull req for v5.18 to pull in some important fixes.
Signed-off-by: NDave Airlie <airlied@redhat.com>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGvwHFHEd+9df-0aBOCfmw+ULvTS3f18sJuq_cvGKLDSjw@mail.gmail.com

It should be p->job->ibs[j] instead of p->job->ibs[i] here.

Fixes: cdc7893f ("drm/amdgpu: use job and ib structures directly in CS parsers")
Signed-off-by: NLang Yu <Lang.Yu@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

it makes no sense to continue with an undefined vmid.

Fixes: c8b0507f ("drm/amdkfd: judge get_atc_vmid_pasid_mapping_info before call")
Signed-off-by: NYifan Zhang <yifan1.zhang@amd.com>
Reported-by: NNathan Chancellor <nathan@kernel.org>
Reviewed-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

Merge tag 'exynos-drm-next-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-next

New feature
- Add BGR pixel format support for FIMD device. As for this,
  this patch uses undocumented register, WIN_RGB_ORDER, but
  it is safe because product kernels have been using same
  register.
Signed-off-by: NDave Airlie <airlied@redhat.com>

From: Inki Dae <inki.dae@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220304085220.324245-1-inki.dae@samsung.com

Currently this will enforce both 2M alignment and padding for any LMEM
pages inserted into the GGTT. However, this was only meant to be applied
to the compact-pt layout with the ppGTT. For the GGTT we can reduce the
alignment and padding to 64K.

Bspec: 45015
Fixes: 87bd701e ("drm/i915: enforce min GTT alignment for discrete cards")
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Robert Beckett <bob.beckett@collabora.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: NThomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303100229.839282-1-matthew.auld@intel.com
(cherry picked from commit c64fa77d)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Avoid going down devfreq paths on devices where devfreq is not
initialized.

v2: Change has_devfreq() logic [Dmitry]
Reported-by: NLinux Kernel Functional Testing <lkft@linaro.org>
Reported-by: NAnders Roxell <anders.roxell@linaro.org>
Signed-off-by: NRob Clark <robdclark@chromium.org>
Fixes: 6aa89ae1 ("drm/msm/gpu: Cancel idle/boost work on suspend")
Reviewed-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220308184844.1121029-1-robdclark@gmail.com

These casts need to happen before the shift.  The only time it would
matter would be if "rev.core" is >= 128.  In that case the sign bit
would be extended and we do not want that.

Fixes: afab9d91 ("drm/msm/adreno: Expose speedbin to userspace")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NAkhil P Oommen <quic_akhilpo@quicinc.com>
Link: https://lore.kernel.org/r/20220307133105.GA17534@kiliSigned-off-by: NRob Clark <robdclark@chromium.org>

- add the missing attribute "name" in VFIO mdev hierarchy.
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
From: "Wang, Zhi A" <zhi.a.wang@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e38f0725-6b22-8e49-b8f6-41986b0ece06@intel.com

The current implementation of the async flip wm0/ddb optimization
does not work at all. The biggest problem is that we skip the
whole intel_pipe_update_{start,end}() dance and thus never actually
complete the commit that is trying to do the wm/ddb change.

To fix this we need to move the do_async_flip flag to the crtc
state since we handle commits per-pipe, not per-plane.

Also since all planes can now be included in the first/last
"async flip" (which gets converted to a sync flip to do the
wm/ddb mangling) we need to be more careful when checking if
the plane state is async flip comptatible. Only planes doing
the async flip should be checked and other planes are perfectly
fine not adhereing to any async flip related limitations.

However for subsequent commits which are actually going do the
async flip in hardware we want to make sure no other planes
are in the state. That should never happen assuming we did our
job correctly, so we'll toss in a WARN to make sure we catch
any bugs here.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: c3639f3b ("drm/i915: Use wm0 only during async flips for DG2")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220214105532.13049-4-ville.syrjala@linux.intel.comReviewed-by: NStanislav Lisovskiy <stanislav.lisovskiy@intel.com>
(cherry picked from commit 2e084371)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Since the async flip state check is done very late and
thus it can see potentially all the planes in the state
(due to the wm/ddb optimization) we need to move the
"can the requested plane do async flips at all?" check
much earlier. For this purpose we introduce
intel_async_flip_check_uapi() that gets called early during
the atomic check.

And for good measure we'll throw in a couple of basic checks:
- is the crtc active?
- was a modeset flagged?
- is+was the plane enabled?
Though atm all of those should be guaranteed by the fact
that the async flip can only be requested through the legacy
page flip ioctl.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: c3639f3b ("drm/i915: Use wm0 only during async flips for DG2")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220214105532.13049-3-ville.syrjala@linux.intel.comReviewed-by: NStanislav Lisovskiy <stanislav.lisovskiy@intel.com>
(cherry picked from commit b0b2bed2)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

data_rate==0 no longer means a plane is disabled, it could
also mean we want to use the minimum ddb allocation for it.
Hence we can't bail out early during ddb allocation or
else we'll simply forget to allocate any ddb for such planes.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: 6a4d8cc6 ("drm/i915: Don't allocate extra ddb during async flip for DG2")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220214105532.13049-2-ville.syrjala@linux.intel.comReviewed-by: NStanislav Lisovskiy <stanislav.lisovskiy@intel.com>
(cherry picked from commit 6475e106)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

bigjoiner_pipes==0 leads bigjoiner_master_pipe() to
do BIT(ffs(0)-1) which is undefined behaviour. The code should
actually still work fine since the only place we provoke
that is intel_crtc_bigjoiner_slave_pipes() and it'll bitwise
AND the result with 0, so doesn't really matter what we get
out of bigjoiner_master_pipe(). But best not provoke undefined
behaviour anyway.
Reported-by: Nkernel test robot <oliver.sang@intel.com>
Fixes: a6e7a006 ("drm/i915: Change bigjoiner state tracking to use the pipe bitmask")
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220223131315.18016-2-ville.syrjala@linux.intel.comReviewed-by: NManasi Navare <manasi.d.navare@intel.com>
(cherry picked from commit cccc71b5)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

To enable compiler type-checked against the format string in callers.

All warnings (new ones prefixed by >>):

>> warning: function 'kfd_smi_event_add' might be a candidate for
'gnu_printf' format attribute [-Wsuggest-attribute=format]

Fixes: d58b8a99 ("drm/amdkfd: Add SMI add event helper")
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NPhilip Yang <Philip.Yang@amd.com>
Reviewed-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

The mdev attribute "name" is required by some middle software, e.g.
KubeVirt, an open source SW that manages VM on Kubernetes cluster uses
the mdev sysfs directory/file structure to discover mediated device in
nodes in the cluster.

v2:

- Fix the missing defination in gvt_type_attrs. (Zhenyu)

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Hui Chun Ong <hui.chun.ong@intel.com>
Cc: Terrence Xu <terrence.xu@intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: NZhi Wang <zhi.wang.linux@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220222150532.9090-1-zhi.a.wang@intel.comReviewed-by: NZhenyu Wang <zhenyuw@linux.intel.com>

refcount_t complains about 0->1 transitions, which isn't *quite* what we
wanted.  So use dirtyfb==1 to mean that the fb is not connected to any
output that requires dirtyfb flushing, so that we can keep the underflow
and overflow checking.

Fixes: 9e4dde28 ("drm/msm: Avoid dirtyfb stalls on video mode displays (v2)")
Signed-off-by: NRob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20220304202146.845566-1-robdclark@gmail.com

Fixes: f6d62d09 ("drm/msm/a6xx: add support for Adreno 660 GPU")
Signed-off-by: NRob Clark <robdclark@chromium.org>
Reviewed-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220305173405.914989-1-robdclark@gmail.com

Add a way for userspace to specify the sequence number fence used to
track completion of the submit.  As the seqno fence is simply an
incrementing counter which is local to the submitqueue, it is easy for
userspace to know the next value.

This is useful for native userspace drivers in a vm guest, as the guest
to host roundtrip can have high latency.  Assigning the fence seqno in
the guest userspace allows the guest to continue without waiting for
response from the host.
Signed-off-by: NRob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20220224222321.60653-1-robdclark@gmail.com

Any app controlled perfcntr collection (GL_AMD_performance_monitor, etc)
does not require counters to maintain state across context switches.  So
clear them if systemwide profiling is not active.
Signed-off-by: NRob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20220304005317.776110-5-robdclark@gmail.com