While working on supporting the Intel HDR backlight interface, I noticed
that there's a couple of laptops that will very rarely manage to boot up
without detecting Intel HDR backlight support - even though it's supported
on the system. One example of such a laptop is the Lenovo P17 1st
generation.
Following some investigation Ville Syrjälä did through the docs they have
available to them, they discovered that there's actually supposed to be a
30ms wait after writing the source OUI before we begin setting up the rest
of the backlight interface.
This seems to be correct, as adding this 30ms delay seems to have
completely fixed the probing issues I was previously seeing. So - let's
start performing a 30ms wait after writing the OUI, which we do in a manner
similar to how we keep track of PPS delays (e.g. record the timestamp of
the OUI write, and then wait for however many ms are left since that
timestamp right before we interact with the backlight) in order to avoid
waiting any longer then we need to. As well, this also avoids us performing
this delay on systems where we don't end up using the HDR backlight
interface.
V3:
* Move last_oui_write into intel_dp
V2:
* Move panel delays into intel_pps
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Fixes: 4a8d79901d ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.12+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211130212912.212044-1-lyude@redhat.com
(cherry picked from commit c7c90b0b84)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This simply adds proper support for panel backlights that can be controlled
via VESA's backlight control protocol, but which also require that we
enable and disable the backlight via PWM instead of via the DPCD interface.
We also enable this by default, in order to fix some people's backlights
that were broken by not having this enabled.
For reference, backlights that require this and use VESA's backlight
interface tend to be laptops with hybrid GPUs, but this very well may
change in the future.
v4:
* Make sure that we call intel_backlight_level_to_pwm() in
intel_dp_aux_vesa_enable_backlight() - vsyrjala
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://gitlab.freedesktop.org/drm/intel/-/issues/3680
Fixes: fe7d52bcca ("drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable")
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.12+
Link: https://patchwork.freedesktop.org/patch/msgid/20211105183342.130810-2-lyude@redhat.com
(cherry picked from commit 04f0d6cc62)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
I got a drm-fixes which had some 5.15 stuff in it, so to avoid
the mess just backmerge here.
Linux 5.15
Signed-off-by: Dave Airlie <airlied@redhat.com>
Couple Reverts, build fix, couple virtualization fixes,
blank screen and other display rates fixes, and more.
Four patches targeting stable in here.
Display Fixes:
- DP rates related fixes (Imre, Jani)
- A Revert on disaling dual eDP that was causing state readout problems (Jani)
- put the cdclk vtables in const data (Jani)
- Fix DVO port type for moder platforms (Ville)
- Fix blankscreen by turning DP++ TMDS output buffers on encoder->shutdown (Ville)
- CCS FBs related fixes (Imre)
GT fixes:
- Fix recursive lock in GuC submission (Matt Brost)
- Revert guc_id from i915_request tracepoint (Joonas)
- Build fix around dmabuf (Matt Auld)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YYsBif3HMi8GjLoU@intel.com
Looks like our VBIOS/GOP generally fail to turn the DP dual mode adater
TMDS output buffers back on after a reboot. This leads to a black screen
after reboot if we turned the TMDS output buffers off prior to reboot.
And if i915 decides to do a fastboot the black screen will persist even
after i915 takes over.
Apparently this has been a problem ever since commit b2ccb822d3 ("drm/i915:
Enable/disable TMDS output buffers in DP++ adaptor as needed") if one
rebooted while the display was turned off. And things became worse with
commit fe0f1e3bfd ("drm/i915: Shut down displays gracefully on reboot")
since now we always turn the display off before a reboot.
This was reported on a RKL, but I confirmed the same behaviour on my
SNB as well. So looks pretty universal.
Let's fix this by explicitly turning the TMDS output buffers back on
in the encoder->shutdown() hook. Note that this gets called after irqs
have been disabled, so the i2c communication with the DP dual mode
adapter has to be performed via polling (which the gmbus code is
perfectly happy to do for us).
We also need a bit of care in handling DDI encoders which may or may
not be set up for HDMI output. Specifically ddc_pin will not be
populated for a DP only DDI encoder, in which case we don't want to
call intel_gmbus_get_adapter(). We can handle that by simply doing
the dual mode adapter type check before calling
intel_gmbus_get_adapter().
Cc: <stable@vger.kernel.org> # v5.11+
Fixes: fe0f1e3bfd ("drm/i915: Shut down displays gracefully on reboot")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4371
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211029191802.18448-2-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
(cherry picked from commit 49c55f7b03)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Atm until the DPCD for a connector is read the max link rate and lane
count params are invalid. If the connector is modeset, in
intel_dp_compute_config(), intel_dp_common_len_rate_limit(max_link_rate)
will return 0, leading to a intel_dp->common_rates[-1] access.
Fix the above by making sure the max link params are always valid.
The above access leads to an undefined behaviour by definition, though
not causing a user visible problem to my best knowledge, see the previous
patch why. Nevertheless it is an undefined behaviour and it triggers a
BUG() in CONFIG_UBSAN builds, hence CC:stable.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018094154.1407705-4-imre.deak@intel.com
(cherry picked from commit 9ad87de473)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Atm, there are no sink rate values set for DP (vs. eDP) sinks until the
DPCD capabilities are successfully read from the sink. During this time
intel_dp->num_common_rates is 0 which can lead to a
intel_dp->common_rates[-1] (*)
access, which is an undefined behaviour, in the following cases:
- In intel_dp_sync_state(), if the encoder is enabled without a sink
connected to the encoder's connector (BIOS enabled a monitor, but the
user unplugged the monitor until the driver loaded).
- In intel_dp_sync_state() if the encoder is enabled with a sink
connected, but for some reason the DPCD read has failed.
- In intel_dp_compute_link_config() if modesetting a connector without
a sink connected on it.
- In intel_dp_compute_link_config() if modesetting a connector with a
a sink connected on it, but before probing the connector first.
To avoid the (*) access in all the above cases, make sure that the sink
rate table - and hence the common rate table - is always valid, by
setting a default minimum sink rate when registering the connector
before anything could use it.
I also considered setting all the DP link rates by default, so that
modesetting with higher resolution modes also succeeds in the last two
cases above. However in case a sink is not connected that would stop
working after the first modeset, due to the LT fallback logic. So this
would need more work, beyond the scope of this fix.
As I mentioned in the previous patch, I don't think the issue this patch
fixes is user visible, however it is an undefined behaviour by
definition and triggers a BUG() in CONFIG_UBSAN builds, hence CC:stable.
v2: Clear the default sink rates, before initializing these for eDP.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4297
References: https://gitlab.freedesktop.org/drm/intel/-/issues/4298
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018143417.1452632-1-imre.deak@intel.com
(cherry picked from commit 3f61ef9777)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reading out the DP encoders' DPCD during booting or resume is only
required for enabled encoders: such encoders may be modesetted during
the initial commit and the link training this involves depends on an
initialized DPCD. For DDI encoders reading out the DPCD is skipped, do
the same on pre-DDI platforms.
Atm, the first DPCD readout without a sink connected - which is a likely
scneario if the encoder is disabled - leaves intel_dp->num_common_rates
at 0, which resulted in
intel_dp_sync_state()->intel_dp_max_common_rate()
in a
intel_dp->common_rates[-1]
access. This by definition results in an undefined behaviour, though to
my best knowledge in all HW/compiler configurations it actually results
in accessing the array item type value preceding the array. In this
case the preceding value happens to be intel_dp->num_common_rates,
which is 0, so this issue - by luck - didn't cause a user visible
problem.
Nevertheless it's still an undefined behaviour and in CONFIG_UBSAN
builds leads to a kernel BUG() (which revealed this problem for us),
hence CC:stable.
A related problem in case the encoder is enabled but the sink is not
connected or the DPCD readout fails is fixed by the next patch.
v2: Amend the commit message describing the root cause of the
CONFIG_UBSAN BUG().
Fixes: a532cde31d ("drm/i915/tc: Fix TypeC port init/resume time sanitization")
References: https://gitlab.freedesktop.org/drm/intel/-/issues/4297
Reported-and-tested-by: Mat Jonczyk <mat.jonczyk@o2.pl>
Cc: Mat Jonczyk <mat.jonczyk@o2.pl>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018094154.1407705-2-imre.deak@intel.com
(cherry picked from commit 4ec5ffc341)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
8b/10b encoding format requires to reserve the first slot for
recording metadata. Real data transmission starts from the second slot,
with a total of available 63 slots available.
In 128b/132b encoding format, metadata is transmitted separately
in LLCP packet before MTP. Real data transmission starts from
the first slot, with a total of 64 slots available.
v2:
* Move total/start slots to mst_state, and copy it to mst_mgr in
atomic_check
v3:
* Only keep the slot info on the mst_state
* add a start_slot parameter to the payload function, to facilitate non
atomic drivers (this is a temporary workaround and should be removed when
we are moving out the non atomic driver helpers)
v4:
*fixed typo and formatting
v5: (no functional changes)
* Fixed formatting in drm_dp_mst_update_slots()
* Reference mst_state instead of mst_state->mgr for debugging info
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
[v5 nitpicks]
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025223825.301703-3-lyude@redhat.com
As per the comment on top of acpi_evaluate_dsm():
| * Evaluate device's _DSM method with specified GUID, revision id and
| * function number. Caller needs to free the returned object.
We should free the returned object of acpi_evaluate_dsm() to avoid memory
leakage. Otherwise the kmemleak splat will be triggered at boot time (if we
compile kernel with CONFIG_DEBUG_TEST_DRIVER_REMOVE=y).
Fixes: 8e55f99c51 ("drm/i915: Invoke another _DSM to enable MUX on HP Workstation laptops")
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210906033541.862-1-yuzenghui@huawei.com
(cherry picked from commit 149ac2e7ae)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Need to resync drm-intel-next with TTM and PXP stuff from
drm-intel-gt-next that is now in drm/drm-next.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
The 128b/132b channel coding link training uses more straightforward TX
FFE preset values. Reuse voltage tries and max vswing for retry logic.
The delays for 128b/132b are still all wrong, but this is regardless a
step forward.
v2: Fix UHBR rate checks, use intel_dp_is_uhbr() helper
v3:
- Rebase
- Modify intel_dp_adjust_request_changed() and
intel_dp_link_max_vswing_reached() to take 128b/132b into
account. (Ville)
v4:
- Train request printing for TX FFE (Ville)
- Log 8b/10b vs. 128b/132b (Ville)
- Add helper for per-lane max vswing / tx ffe (Ville)
- Name functions with tx_ffe/vswing instead of 128b132b/8b10b
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211011182144.22074-2-jani.nikula@intel.com
UAPI Changes:
- Add uAPI for using PXP protected objects
Mesa changes: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8064
- Add PCI IDs and LMEM discovery/placement uAPI for DG1
Mesa changes: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11584
- Disable engine bonding on Gen12+ except TGL, RKL and ADL-S
Cross-subsystem Changes:
- Merges 'tip/locking/wwmutex' branch (core kernel tip)
- "mei: pxp: export pavp client to me client bus"
Core Changes:
- Update ttm_move_memcpy for async use (Thomas)
Driver Changes:
- Enable GuC submission by default on DG1 (Matt B)
- Add PXP (Protected Xe Path) support for Gen12 integrated (Daniele,
Sean, Anshuman)
See "drm/i915/pxp: add PXP documentation" for details!
- Remove force_probe protection for ADL-S (Raviteja)
- Add base support for XeHP/XeHP SDV (Matt R, Stuart, Lucas)
- Handle DRI_PRIME=1 on Intel igfx + Intel dgfx hybrid graphics setup (Tvrtko)
- Use Transparent Hugepages when IOMMU is enabled (Tvrtko, Chris)
- Implement LMEM backup and restore for suspend / resume (Thomas)
- Report INSTDONE_GEOM values in error state for DG2 (Matt R)
- Add DG2-specific shadow register table (Matt R)
- Update Gen11/Gen12/XeHP shadow register tables (Matt R)
- Maintain backward-compatible nested batch behavior on TGL+ (Matt R)
- Add new LRI reg offsets for DG2 (Akeem)
- Initialize unused MOCS entries to device specific values (Ayaz)
- Track and use the correct UC MOCS index on Gen12 (Ayaz)
- Add separate MOCS table for Gen12 devices other than TGL/RKL (Ayaz)
- Simplify the locking and eliminate some RCU usage (Daniel)
- Add some flushing for the 64K GTT path (Matt A)
- Mark GPU wedging on driver unregister unrecoverable (Janusz)
- Major rework in the GuC codebase, simplify locking and add docs (Matt B)
- Add DG1 GuC/HuC firmwares (Daniele, Matt B)
- Remember to call i915_sw_fence_fini on guc_state.blocked (Matt A)
- Use "gt" forcewake domain name for error messages instead of "blitter" (Matt R)
- Drop now duplicate LMEM uAPI RFC kerneldoc section (Daniel)
- Fix early tracepoints for requests (Matt A)
- Use locked access to ctx->engines in set_priority (Daniel)
- Convert gen6/gen7/gen8 read operations to fwtable (Matt R)
- Drop gen11/gen12 specific mmio write handlers (Matt R)
- Drop gen11 specific mmio read handlers (Matt R)
- Use designated initializers for init/exit table (Kees)
- Fix syncmap memory leak (Matt B)
- Add pretty printing for buddy allocator state debug (Matt A)
- Fix potential error pointer dereference in pinned_context() (Dan)
- Remove IS_ACTIVE macro (Lucas)
- Static code checker fixes (Nathan)
- Clean up disabled warnings (Nathan)
- Increase timeout in i915_gem_contexts selftests 5x for GuC submission (Matt B)
- Ensure wa_init_finish() is called for ctx workaround list (Matt R)
- Initialize L3CC table in mocs init (Sreedhar, Ayaz, Ram)
- Get PM ref before accessing HW register (Vinay)
- Move __i915_gem_free_object to ttm_bo_destroy (Maarten)
- Deduplicate frequency dump on debugfs (Lucas)
- Make wa list per-gt (Venkata)
- Do not define dummy vma in stack (Venkata)
- Take pinning into account in __i915_gem_object_is_lmem (Matt B, Thomas)
- Do not report currently active engine when describing objects (Tvrtko)
- Fix pdfdocs build error by removing nested grid from GuC docs (Akira)
- Remove false warning from the rps worker (Tejas)
- Flush buffer pools on driver remove (Janusz)
- Fix runtime pm handling in i915_gem_shrink (Maarten)
- Rework TTM object initialization slightly (Thomas)
- Use fixed offset for PTEs location (Michal Wa)
- Verify result from CTB (de)register action and improve error messages (Michal Wa)
- Fix bug in user proto-context creation that leaked contexts (Matt B)
- Re-use Gen11 forcewake read functions on Gen12 (Matt R)
- Make shadow tables range-based (Matt R)
- Ditch the i915_gem_ww_ctx loop member (Thomas, Maarten)
- Use NULL instead of 0 where appropriate (Ville)
- Rename pci/debugfs functions to respect file prefix (Jani, Lucas)
- Drop guc_communication_enabled (Daniele)
- Selftest fixes (Thomas, Daniel, Matt A, Maarten)
- Clean up inconsistent indenting (Colin)
- Use direction definition DMA_BIDIRECTIONAL instead of
PCI_DMA_BIDIRECTIONAL (Cai)
- Add "intel_" as prefix in set_mocs_index() (Ayaz)
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YWAO80MB2eyToYoy@jlahtine-mobl.ger.corp.intel.com
Signed-off-by: Dave Airlie <airlied@redhat.com>
Limit the supported UHBR rates based on the repeater support, if there
are repeaters.
This should be done in DP helper level, but that requires an overhaul of
the LTTPR handling, as the max rate is not enough to represent how
128b/132b rates may be masked along the way.
Curiously, the spec says:
* Shall be cleared to 00h when operating in 8b/10b Link Layer.
* Each LTTPR on the way back to the DPTX shall clear the bits that do
not correspond to the LTTPR's current bit rate.
It's rather vague if we can reliably use the field at this time due to
the wording "operating" and "current". But it would seem bizarre to have
to wait until trying to operate a 128b/132b link layer at a certain bit
rate to figure this out.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211007105727.18439-1-jani.nikula@intel.com
As per the comment on top of acpi_evaluate_dsm():
| * Evaluate device's _DSM method with specified GUID, revision id and
| * function number. Caller needs to free the returned object.
We should free the returned object of acpi_evaluate_dsm() to avoid memory
leakage. Otherwise the kmemleak splat will be triggered at boot time (if we
compile kernel with CONFIG_DEBUG_TEST_DRIVER_REMOVE=y).
Fixes: 8e55f99c51 ("drm/i915: Invoke another _DSM to enable MUX on HP Workstation laptops")
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210906033541.862-1-yuzenghui@huawei.com
Unify all debug prints during link training to include information
on both the encoder and the LTTPR. We unify the format to something
like "[ENCODER:1:FOO][LTTPR 1] Something something". Though not
sure if those brackets around the dp_phy just make it look like
line noise? I'll accept suggestions on better formatting.
I'm slightly on the fence about also including the connector,
but technically only the DPRX is the SST connector (ie.
intel_dp->attached_connector). I suppose you could think of it
as the branch device/whatever in the topology, and we're training
the link leading to it. So that could argue for its inclusion.
But it's all getting a bit long alrady, so not going to do it
I think.
v2: Keep the connector name in the final passed/failed debug print
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211004170535.4173-5-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
Currently we consider the max vswing reached when we transmit a
the max voltage level, but we don't consider pre-emphasis at all.
This kinda matches older DP specs that only had some vague text
about transmitting the maximum voltage swing. Latest versions
now say something vague about consider the sum of the vswing
and pre-emphasis fields in the ADJUST_REQUEST_LANE registers.
Very vague, and super confusing especially the fact that it
talks about transmitted voltgage swing in the same sentence
as it say to look at the requested values.
Also glanced at the link CTS spec, and that one seems to have
tests that assume contradicting behaviour. Some say to consider
just the vswing level we transmit, others say to check for
sum of transmitted vswing+preemph being 3.
So let's try to take some kind of sane middle ground here.
I think what could make sense is only consider max vswing
reached if MAX_SWING_REACHED==1 _and_ vswing+preemph==3.
That will allow things to go all the way up to vswing 3 +
pre-emph 0 or vswing 2 + pre-emph 1, depending on what
the maximum supported vswing is. Only considering the sum
of vswing+pre-emph doesn't make much sense to me since
we could terminate too early if the sink requests eg.
vswing 0 + pre-emph 3. And if we'd stick to the current
code we could terminate too early of the sink asks for
vswing 2 + pre-emph 0 when vswing level 3 is not supported.
Side note: I don't really understand why any of this stuff is
"specified" at all. There is already a limit of 5 attempts at
the same vswing+pre-emph level, and a total limit of 10
attempts. So might as well stick to the same max 5 attempts
across the board IMO.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211004170535.4173-2-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
With patch "drm/i915/vbt: Fix backlight parsing for VBT 234+"
the size of bdb_lfp_backlight_data structure has been increased,
causing if-statement in the parse_lfp_backlight function
that comapres this structure size to the one retrieved from BDB,
always to fail for older revisions.
This patch calculates expected size of the structure for a given
BDB version and compares it with the value gathered from BDB.
Tested on Chromebook Pixelbook (Nocturne) (reports bdb->version = 221)
Fixes: d381baad29 ("drm/i915/vbt: Fix backlight parsing for VBT 234+")
Tested-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Lukasz Majczak <lma@semihalf.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930134606.227234-1-lma@semihalf.com
(cherry picked from commit 4378daf5d0)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
