We need to start parsing stuff from the tail end of the LFP data block.
This is made awkward by the fact that the fp_timing table has variable
size. So we must use a bit more finesse to get the tail end, and to
make sure we allocate enough memory for it to make sure our struct
representation fits.

v2: Rebase due to the preallocation of BDB blocks
v3: Rebase due to min_size WARN relocation
v4: Document BDB_LVDS_LFP_DATA vs. BDB_LVDS_LFP_DATA_PTRS order (Jani)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220504150440.13748-4-ville.syrjala@linux.intel.com

Modern VBTs no longer contain the LFP data table pointers
block (41). We are expecting to have one in order to be able
to parse the LFP data block (42), so let's make one up.

Since the fp_timing table has variable size we must somehow
determine its size. Rather than just hardcode it we look for
the terminator bytes (0xffff) to figure out where each table
entry starts. dvo_timing, panel_pnp_id, and panel_name are
expected to have fixed size.

This has been observed on various machines, eg. TGL with BDB
version 240, CML with BDB version 231, etc. The most recent
VBT I've observed that still had block 41 had BDB version
228. So presumably the cutoff (if an exact cutoff even exists)
is somewhere around BDB version 229-231.

v2: kfree the thing we allocated, not the thing+3 bytes
v3: Do the debugprint only if we found the LFP data block
v4: Fix t0 null check (Jani)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220504150440.13748-3-ville.syrjala@linux.intel.com

Reorder things so that we can parse the entier LFP data block
in one go. For now we just stick to parsing the DTD from it.

Also fix the misleading comment about block 42 being deprecated.
Only the DTD part is deprecated, the rest is still very much needed.

v2: Move the version check+comment into parse_generic_dtd() (Jani)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220504150440.13748-2-ville.syrjala@linux.intel.com

In addition to the fp_timing,dvo_timing,panel_pnp_id tables
there also exists a panel_name table. Unlike the others this
is just one offset+table_size even though there are still 16
actual panel_names in the data block.

The panel_name table made its first appearance somewhere
around VBT version 156-163. The exact version is not known.
But we don't need to know that since we can just check whether
the pointers block has enough room for it or not.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-7-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Now that we've sufficiently validated the LFP data pointers we
can trust them.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-6-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Make sure the LFP data table pointers sane. Sensible looking
table entries, everything points correctly into the data block,
etc.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-5-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Currently get_lvds_fp_timing() still returns a pointer to the original
data block rather than our copy. Let's convert the data pointer offsets
to be relative to the data block rather than the whole BDB. With that
we can make get_lvds_fp_timing() return a pointer to the copy.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-4-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Make a copy of each VBT data block with a guaranteed minimum
size. The extra (if any) will just be left zeroed.

This means we don't have to worry about going out of bounds
when accessing any of the structure members. Otherwise that
could easliy happen if we simply get the version check wrong,
or if the VBT is broken/malicious.

v2: Don't do arithmetic between bdb header and copy
    of the LFP data block (Jani)
v3: Make all the copies up front
v4: Only WARN about min_size==0 if we found the block
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220406133817.30652-1-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

We have the BDB version cached, use it. We're going to have to
start doing some of the BDB block parsing later, at which point
we may no longer have the VBT around anymore (we free it at the
end of intel_bios_init() when it didn't come via OpRegion).
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405173410.11436-2-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

All the LFP data table pointers have uniform layout. Turn
that into a struct.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220317171948.10400-2-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Replace all drm_mode_debug_printmodeline() calls with
DRM_MODE_FMT+DRM_MODE_ARG(). Makes the debug output a bit more
terse in places where we previously had a newline in the precedeing
drm_dbg_kms(), and avoids anything else sneaking in between the two
printk()s in all cases.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323182935.4701-3-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Make the drrs type enum less convoluted.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220310004802.16310-7-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

VBT hsa a field for the MSA timing delay, which supposedly
should be used with DRRS. Extract the data from the VBT.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220310004802.16310-5-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

VBT 249 update to support more TMDS clock rate 3.00G, 3.40G
and 5.94G. Refer to this new definition to configure max
TMDS clock rate for HDMI driver.

BSpec: 20124

v2: new subject

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NLee Shawn C <shawn.c.lee@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303083802.5071-1-shawn.c.lee@intel.com

A new programming step was added to combo and TC PLL sequences.
If override_AFC_startup is set in VBT, driver should overwrite
AFC_startup value to 0x0 or 0x7 in PLL's div0 register.

The current understating is that only TGL needs this and all other
display 12 and newer platforms will have a older VBT or a newer VBT
with override_AFC_startup set to 0 but in any case there is a
drm_warn_on_once() to let us know if this is not true.

v2:
- specification updated, now AFC can be override to 0x0 or 0x7
- not using a union for div0 (Imre)
- following previous wrong vbt naming: bits instead of bytes (Imre)

BSpec: 49204
BSpec: 20122
BSpec: 49968
BSpec: 71360
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220216134059.25348-1-jose.souza@intel.com

Several of our i915 header files, have been including i915_reg.h.  This
means that any change to i915_reg.h will trigger a full rebuild of
pretty much every file of the driver, even those that don't have any
kind of register access.  Let's delete the i915_reg.h include from all
headers and add an explicit include from the .c files that truly
need the register definitions; those that need a definition of
i915_reg_t for a function definition can get it from i915_reg_defs.h
instead.

We also remove two non-register #define's (VLV_DISPLAY_BASE and
GEN12_SFC_DONE_MAX) into i915_reg_defs.h to allow us to drop the
i915_reg.h include from a couple of headers.

There's probably a lot more header dependency optimization possible, but
the changes here roughly cut the number of files compiled after 'touch
i915_reg.h' in half --- a good first step.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: NLucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220127234334.4016964-7-matthew.d.roper@intel.com

Replace the DEVICE_TYPE_DP_DUAL_MODE_BITS stuff with just
a DP+HDMI check. The rest of the bits shouldn't really
matter anyway.

The slight change in behaviour here is that now we do look at
the DEVICE_TYPE_NOT_HDMI_OUTPUT bit (via
intel_bios_encoder_supports_hdmi()) when we previously ignored it.
The one platform we know that has problems with that bit is VLV.
But IIRC the problem was always that buggy VBTs basically never
set that bit. So that should be OK since all it would do is make
all DVI ports look like HDMI ports instead. Also can't imagine
there are many VLV machines with actual DVI ports in existence.

We still keep the rest of the dvo_port/aux_ch checks as we
can't trust that DP+HDMI device type equals DP++ due to
buggy VBTs.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211217155403.31477-6-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Now that we parse the DDI port info from the VBT on all g4x+ platforms
we can throw out all the old codepaths in intel_bios_is_port_present(),
intel_bios_is_port_edp() and intel_bios_is_port_dp_dual_mode(). None
of these should be called on pre-g4x platforms.

For good measure throw in a WARN into intel_bios_is_port_present()
should someone get the urge to call it on older platforms. The
other two functions are specific to HDMI and DP so should not need
any protection as those encoder types don't even exist on older
platforms.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211217155403.31477-5-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Extend the vbt.ports[] stuff for all g4x+ platforms. We do need
to drop the version check as some elk/ctg machines may have VBTs
older than that. The oldest I know is an elk with version 142.
But the child device stuff has had the correct size since at
least version 125 (observed on my sdg), so from that angle this
should be totally safe.

This does couple of things:
- Start using the aux_ch/ddc_pin from VBT instead of just the
  hardcoded defaults. Hopefully there are no VBTs with entirely
  bogus information here.
- Start using i915->vbt.ports[] for intel_bios_is_port_dp_dual_mode().
  Should be fine as the logic doesn't actually change.
- Start using i915->vbt.ports[] for intel_bios_is_port_edp().
  The old codepath only looks at the DP DVO ports, the new codepath
  looks at both DP and HDMI DVO ports. In principle that should not
  matter. We also stop looking at some of the other device type bits
  (eg. LVDS,MIPI,ANALOG,etc.). Hopefully no VBT is broken enough that
  it sets up totally conflicting device type bits (eg. LVDS+eDP at the
  same time). We also lose the "g4x->no eDP ever" hardcoding (shouldn't
  be hard to re-introduce that into eg. sanitize_device_type() if needed).

Lightly smoke tested on a set of machines (one of ctg,ilk,snb,ivb each)
with both DP and HDMI (DP++). Everything still worked as it should.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211217155403.31477-4-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

CHV is currently straddling the divide by using parse_ddi_ports() stuff
for aux_ch/ddc_pin but going through all old codepaths for the rest
(intel_bios_is_port_present(), intel_bios_is_port_edp(),
intel_bios_is_port_dp_dual_mode()). Let's switch over full and use
i915->vbt.ports[] for the rest of the stuff.

dvo_port_to_port() doesn't know about DSI so we won't get into
any kind of "is port B HDMI or DSI or both?" conundrum, which
could otherwise happen on VLV/CHV due to DSI ports living in a
separate world from the other digital ports.

Including Jani's detailed analysis here for posterity:
"We stop checking for port A for CHV in intel_bios_is_port_present(), but
 it's a warn and I don't recall any bug reports, so probably fine. We
 could add a check in parse_ddi_port(), but meh.

 Ditto for intel_bios_is_port_dp_dual_mode(), except it doesn't have a
 warn.

 The eDP check in intel_bios_is_port_edp() becomes slightly more
 relaxed. Both the old and new check require these to be set:

 - DEVICE_TYPE_DISPLAYPORT_OUTPUT
 - DEVICE_TYPE_INTERNAL_CONNECTOR.

 The old code also required these to be unset:

 - DEVICE_TYPE_MIPI_OUTPUT
 - DEVICE_TYPE_COMPOSITE_OUTPUT
 - DEVICE_TYPE_DUAL_CHANNEL
 - DEVICE_TYPE_LVDS_SIGNALING
 - DEVICE_TYPE_TMDS_DVI_SIGNALING
 - DEVICE_TYPE_VIDEO_SIGNALING
 - DEVICE_TYPE_ANALOG_OUTPUT

 It's possible we've added these just as a sanity check for broken VBTs
 more than anything. I guess I'd see if actual problems arise.

 Bottom line, I think the functional changes matter only for VBTs with
 bogus data."

I agree that it should work assuming the VBT isn't totally insane.
Modern windows drivers also don't seem to check any of those
additional device type bits, which may or may not matter for older
devices (no idea what some old driver versions are checking).
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211217155403.31477-3-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Pull the "do we want to use i915->vbt.ports[]?" check into
a central place.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211217155403.31477-2-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

Move all public DisplayPort headers into dp/ and update users. No
functional changes.

v3:
	* rebased onto latest drm-tip
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NDaniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220114114535.29157-5-tzimmermann@suse.de

The lines_to_wait info from VBT is never used. Remove.

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220112112715.1234366-1-jani.nikula@intel.com

If VBT size is not a multiple of 4, the last 4-byte store will be out of
bounds of the allocated buffer. Spotted with KASAN. Round up the
allocation size.

v2: Use round_up() intead of roundup() as it's a power of 2 (Thomas)
Reported-by: NThomas Hellström <thomas.hellstrom@linux.intel.com>
Fixes: a36e7dc0 ("drm/i915/dg1: Read OPROM via SPI controller")
Cc: Clint Taylor <clinton.a.taylor@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NThomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211222081654.1843211-1-jani.nikula@intel.com

Read OPROM SPI through MMIO and find VBT entry since we can't use
OpRegion and PCI mapping may not work on some systems due to most BIOSes
not leaving the Option ROM mapped.

v2: Remove message with allocation failure

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NClint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211216062645.3477854-1-lucas.demarchi@intel.com

From VBT, ddc pin info suggests the following mapping:
    VBT                                    DRIVER
    DDI TC1->ddc_pin=3 should translate to PORT_TC1->0x9
    DDI TC2->ddc_pin=4 should translate to PORT_TC2->0xa
    DDI TC3->ddc_pin=5 should translate to PORT_TC3->0xb
    DDI TC4->ddc_pin=6 should translate to PORT_TC4->0xc

Adding pin map to facilitate this translation as we cannot use existing
icl ddc pin map due to conflict with DDI C and DDI TC1 info.

Bspec:20124

v2:
  - Changed Author to Tejas Upadhyay

Cc: Clinton Taylor <Clinton.A.Taylor@intel.com>
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Acked-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NLee Shawn C <shawn.c.lee@intel.com>
Signed-off-by: NTejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
Signed-off-by: NRaviteja Goud Talla <ravitejax.goud.talla@intel.com>
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211203073720.3823371-1-ravitejax.goud.talla@intel.com

Looks like we never updated intel_bios_is_port_dp_dual_mode() when
the VBT port mapping became erratic on modern platforms. This
is causing us to look up the wrong child device and thus throwing
the heuristic off (ie. we might end looking at a child device for
a genuine DP++ port when we were supposed to look at one for a
native HDMI port).

Fix it up by not using the outdated port_mapping[] in
intel_bios_is_port_dp_dual_mode() and rely on
intel_bios_encoder_data_lookup() instead.

Cc: stable@vger.kernel.org
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4138Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025142147.23897-1-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>
(cherry picked from commit 32c2bc89)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

Looks like we never updated intel_bios_is_port_dp_dual_mode() when
the VBT port mapping became erratic on modern platforms. This
is causing us to look up the wrong child device and thus throwing
the heuristic off (ie. we might end looking at a child device for
a genuine DP++ port when we were supposed to look at one for a
native HDMI port).

Fix it up by not using the outdated port_mapping[] in
intel_bios_is_port_dp_dual_mode() and rely on
intel_bios_encoder_data_lookup() instead.

Cc: stable@vger.kernel.org
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4138Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025142147.23897-1-ville.syrjala@linux.intel.comReviewed-by: NJani Nikula <jani.nikula@intel.com>

This reverts commit 05734ca2.

It's not graceful, instead it leads to boot time warning splats in the
case it is supposed to handle gracefully. Apparently the BIOS/GOP
enabling the port we end up skipping leads to state readout
problems. Back to the drawing board.

References: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21255/bat-adlp-4/boot0.txt
Fixes: 05734ca2 ("drm/i915/bios: gracefully disable dual eDP for now")
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211019114334.24643-1-jani.nikula@intel.com
(cherry picked from commit 171c555c)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

This reverts commit 05734ca2.

It's not graceful, instead it leads to boot time warning splats in the
case it is supposed to handle gracefully. Apparently the BIOS/GOP
enabling the port we end up skipping leads to state readout
problems. Back to the drawing board.

References: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_21255/bat-adlp-4/boot0.txt
Fixes: 05734ca2 ("drm/i915/bios: gracefully disable dual eDP for now")
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211019114334.24643-1-jani.nikula@intel.com

For the time being, neither the power sequencer nor the backlight code
properly support two eDP panels simultaneously. While the software
states will be independent, the same sets of registers will be used for
both eDP panels, clobbering the hardware state and leading to errors.

Gracefully disable dual eDP until proper support has been added.

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NSwati Sharma <swati2.sharma@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005175636.24669-1-jani.nikula@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: d381baad ("drm/i915/vbt: Fix backlight parsing for VBT 234+")
Tested-by: NLukasz Majczak <lma@semihalf.com>
Signed-off-by: NLukasz Majczak <lma@semihalf.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930134606.227234-1-lma@semihalf.com
(cherry picked from commit 4378daf5)
Signed-off-by: NJani Nikula <jani.nikula@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: d381baad ("drm/i915/vbt: Fix backlight parsing for VBT 234+")
Tested-by: NLukasz Majczak <lma@semihalf.com>
Signed-off-by: NLukasz Majczak <lma@semihalf.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930134606.227234-1-lma@semihalf.com

So far, DCS backlight driver hardcode (0xFF) for max brightness level.
MIPI DCS spec allow max 0xFFFF for set_display_brightness (51h) command.
And VBT brightness precision bits can support 8 ~ 16 bits.

We should set correct precision bits in VBT that meet panel's request.
Driver can refer to this setting then configure max brightness level
in DCS backlight driver properly.

v2: modify variable name brightness_precision_bits instead of
    max_brightness_level.
v3: fix checkpatch warning.

Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: William Tseng <william.tseng@intel.com>
Signed-off-by: NLee Shawn C <shawn.c.lee@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NVandita Kulkarni <vandita.kulkarni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210908115607.9633-5-shawn.c.lee@intel.com

We can finally remove the extra caching in ddi_port_info. Good riddance.

v2: Rebased

Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f56e864d10bb3cbe616288450d92b56325d1df12.1630512523.git.jani.nikula@intel.com

Avoid extra caching of the data. This is slightly more subtle than one
would think. For one thing, we explicitly ignore 0 value in child device
ddc pin; this is specified as N/A and does not warrant a warning. For
another, we start looking for ddc pin collisions in sanitize using
unmapped pin numbering.

v2: Check !devdata in intel_bios_alternate_ddc_pin()

Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e1dbf7cbdd2191439e760ab9098242dcec5fbb2e.1630512523.git.jani.nikula@intel.com

Move code around to avoid a forward declaration in the future.

Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/8c5f723e0b2d8ffd6f47068edf710947b45843be.1630512523.git.jani.nikula@intel.com

Avoid extra caching of the data.

v2: Check for !info->devdata in intel_bios_port_aux_ch() (Ankit)

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b1b9f0032b353c3279b4546d6acdb696fe0b6136.1630512523.git.jani.nikula@intel.com

Avoid extra caching of the data.

Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5593ce81f6670dc33cf18fa284f8237c875ef404.1630512523.git.jani.nikula@intel.com

Avoid extra caching of the data.

Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: NAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/451082780a8befb2b27919439c901a2159ce173f.1630512523.git.jani.nikula@intel.com