To prepare for a follow-up LTTPR change factor out a helper to disable
the training pattern in DPCD. We'll need to do this for each LTTPR
(without programming the port to output the idle pattern) when training
in LTTPR non-transparent mode.

While at it also move the disable-link-training logic from
intel_dp_set_link_train() to intel_dp_stop_link_train(), since the
latter is the only user of this.

v2:
- Move the disable-link-training logic to intel_dp_stop_link_train()
  (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007170917.1764556-4-imre.deak@intel.com

Split the prepare, link training, fallback-handling steps into their own
functions for clarity and as a preparation for the upcoming LTTPR
changes.

While at it also:
- Unexport and inline intel_dp_set_idle_link_train(), which is used at a
  single place.
- Add some documentation to functions that are exported or that can use
  a better description about which part of the LT sequence they
  implement.

v2: (Ville)
- Unexport/inline intel_dp_set_idle_link_train()
- Make the documentation of
  intel_dp_prepare_link_train()/intel_dp_stop_link_train() more accurate
  wrt. HW specific details.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007170917.1764556-3-imre.deak@intel.com

An LTTPR can be trained with training pattern 4 even if the DPCD
revision is < 1.4, but drm_dp_training_pattern_mask() would change
pattern 4 to pattern 3 on those DPCD revisions.

Since intel_dp_training_pattern() makes already sure that the proper
training pattern is used, all that needs to be masked out is the
scrambling disable flag, which is or'd to the mask later based on the
training pattern.

v2:
- Use a helper instead of open-coding the masking. (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007170917.1764556-2-imre.deak@intel.com

Get rid of mode crtc->config usage, and some ad-hoc intel_dp state
usage by plumbing the crtc state all the way down to the link training
code.

Unfortunately we do have to keep some cached state in intel_dp so
that we can do the "does the link need retraining?" checks from
the short hpd handler.

v2: Add intel_crtc_state forward declaration
v3: Don't kill the PHY test code totally since it's
    now in the hotplug work where we can get at the states
v4: Don't resurrect the debug scrambling disable bit (Imre)
    Use intel_dp_mst_is_master_trans() (Imre)
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201001111053.24451-1-ville.syrjala@linux.intel.com

Hours Of Battery Life is a new GEN12+ power-saving feature that allows
supported motherboards to use a special voltage swing table for eDP
panels that uses less power.

So here if supported by HW, OEM will set it in VBT and i915 will try
to train link with HOBL vswing table if link training fails it fall
back to the original table.

intel_ddi_dp_preemph_max() was optimized to only check the HOBL flag
instead of do something like is done in intel_ddi_dp_voltage_max()
because it is only called after the first entry of the voltage swing
table was loaded so the HOBL flag is valid at that point.

v3:
- removed a few parameters of icl_ddi_combo_vswing_program() that
can be taken from encoder

v4:
- using the HOBL vswing table until training fails completely (Ville)

v5:
- not reducing lane or link rate when link training fails with HOBL
active
- duplicated the HOBL voltage swing entry to match DP spec requirement

v6:
- removed the optional VS 3 & pre-emp 0 from HOBL table
- changed from u8:1 to bool to store hobl_failed/active

BSpec: 49291
BSpec: 49399
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NJosé Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200715175637.33763-1-jose.souza@intel.comSigned-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

According to the DP spec a DPTX must support vswing/pre-emphasis
up to and including level 2. Level 3 is optional (actually DP 1.4a
seems to make even level 3 mandatory for HBR2/3, while leaving it
optional for RBR/HBR1).

WARN if out encoders' .voltage_max()/.preemph_max() return
an illegal value.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.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/20200709145845.18118-1-ville.syrjala@linux.intel.com

The DP spec says:
"The transmitter shall support at least three levels of voltage
 swing (Levels 0, 1, and 2).

 If only three levels of voltage swing are supported (VOLTAGE
 SWING SET field (bits 1:0) are programmed to 10 (Level 2)),
 this bit shall be set to 1, and cleared in all other cases.

 If all four levels of voltage swing are supported (VOLTAGE
 SWING SET field (bits 1:0) are programmed to 11 (Level 3)),
 this bit shall be set to 1,and cleared in all other cases."

Let's follow that exactly instead of the current apporach
where we can set those also for vswing/preemph levels 0 or 1
(or 2 when the platform max is 3).
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-7-ville.syrjala@linux.intel.comReviewed-by: NImre Deak <imre.deak@intel.com>

Use max() instead of hand rolling it.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-8-ville.syrjala@linux.intel.comReviewed-by: NManasi Navare <manasi.d.navare@intel.com>

The DP spec says:
"When the combination of the requested pre-emphasis level and
 voltage swing exceeds the capability of a DPTX, the DPTX shall
 set the pre-emphasis level according to the request and use the
 highest voltage swing it can output with the given pre-emphasis level."
and
"When a DPTX reads a request beyond the limits of this Standard,
 the DPTX shall set the pre-emphasis level according to the request
 and set the highest voltage swing level it can output with the
 given pre-emphasis level. If a DPTX is requested for 9.5dB of
 pre-emphasis level (may be supported for a DPTX) and cannot support
 that level, it shall set the pre-emphasis level to the next
 highest level, 6dB."

Ie. we should first validate the pre-emphasis, and then select
the appropriate vswing for it.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-6-ville.syrjala@linux.intel.comReviewed-by: NManasi Navare <manasi.d.navare@intel.com>

Different platforms have different max vswing/preemph settings.
Turn that into a pair vfuncs so we can decouple intel_dp.c and
intel_ddi.c further.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-5-ville.syrjala@linux.intel.comReviewed-by: NManasi Navare <manasi.d.navare@intel.com>

vswing/pre-emphasis adjustment calculation is needed in processing
of auto phy compliance request other than link training, so have
made non-static function.

No functional change.

v1: initial patch.
v2:
- used "intel_dp" prefix in function name. (Jani)
- used array notation instead pointer for link_status. (Ville)
v3: Scrapped the initial patch, modified commit description accordingly.
- made non-static function and used intel_dp prefix. (Jani, Manasi)
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NAnimesh Manna <animesh.manna@intel.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200316103759.12867-4-animesh.manna@intel.com

Converts various instances of the printk based drm logging macros to the
struct drm_device based logging macros in
i915/display/intel_dp_link_training.c.
This also involves extracting the drm_i915_private device pointer from
the intel_dp type to use in the various macros.
Signed-off-by: NWambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200206080014.13759-3-wambui.karugax@gmail.com

Everything about the file is about display, and mostly about types
related to display. Move under display/ as intel_display_types.h to
reflect the facts.

There's still plenty to clean up, but start off with moving the file
where it logically belongs and naming according to contents.

v2: fix the include guard name in the renamed file
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190806113933.11799-1-jani.nikula@intel.com

Add a new subdirectory for display code, and start off by moving
modesetting output/encoder code. Judging by the include changes, this is
a surprisingly clean operation.

v2:
- move intel_sdvo_regs.h too
- use tabs for Makefile	file lists and sort them

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613084416.6794-2-jani.nikula@intel.com

It used to be handy that we only had a couple of headers, but over time
intel_drv.h has become unwieldy. Extract declarations to a separate
header file corresponding to the implementation module, clarifying the
modularity of the driver.

Ensure the new header is self-contained, and do so with minimal further
includes, using forward declarations as needed. Include the new header
only where needed, and sort the modified include directives while at it
and as needed.

No functional changes.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/eb23be64d04957b2cf82b79fd69cc57ed84043a4.1556540889.git.jani.nikula@intel.com

It used to be handy that we only had a couple of headers, but over time
intel_drv.h has become unwieldy. Extract declarations to a separate
header file corresponding to the implementation module, clarifying the
modularity of the driver.

Ensure the new header is self-contained, and do so with minimal further
includes, using forward declarations as needed. Include the new header
only where needed, and sort the modified include directives while at it
and as needed.

No functional changes.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f86f9beed730eaad0bdcc18b18817b3d221e16e2.1554461791.git.jani.nikula@intel.com

Mixed C99 and kernel types use is getting ugly. Prefer kernel types.

sed -i 's/\buint\(8\|16\|32\|64\)_t\b/u\1/g'

Minor checkpatch/whitespace fixes sprinkled on top of the changed lines.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.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/3c030a12b4313eec512ce2b7a953cff439d8af67.1547629303.git.jani.nikula@intel.com

This patch fixes the original commit c0cfb10d ("drm/i915/edp:
Do not do link training fallback or prune modes on EDP") that causes
a blank screen in case of certain eDP panels (Eg: seen on Dell XPS13 9350)
where first link training fails and a retraining is required by falling
back to lower link rate/lane count.
In case of some panels they advertise higher link rate/lane count
than whats required for supporting the panel's native mode.
But we always link train at highest link rate/lane count for eDP
and if that fails we can still fallback to lower link rate/lane count
as long as the fallback link BW still fits the native mode to avoid
pruning the panel's native mode yet retraining at fallback values
to recover from a blank screen.

v3:
* Add const for fixed_mode (Ville)
v2:
* Send uevent if link failure on eDP unconditionally

Fixes: c0cfb10d ("drm/i915/edp: Do not do link training fallback or prune modes on EDP")
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: <stable@vger.kernel.org> # v4.17+
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107489
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105338Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Tested-by: NAlexander Wilson <alexander.wilson@ncf.edu>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181009212804.702-1-manasi.d.navare@intel.com
(cherry picked from commit 1e712535)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

This patch fixes the original commit c0cfb10d ("drm/i915/edp:
Do not do link training fallback or prune modes on EDP") that causes
a blank screen in case of certain eDP panels (Eg: seen on Dell XPS13 9350)
where first link training fails and a retraining is required by falling
back to lower link rate/lane count.
In case of some panels they advertise higher link rate/lane count
than whats required for supporting the panel's native mode.
But we always link train at highest link rate/lane count for eDP
and if that fails we can still fallback to lower link rate/lane count
as long as the fallback link BW still fits the native mode to avoid
pruning the panel's native mode yet retraining at fallback values
to recover from a blank screen.

v3:
* Add const for fixed_mode (Ville)
v2:
* Send uevent if link failure on eDP unconditionally

Fixes: c0cfb10d ("drm/i915/edp: Do not do link training fallback or prune modes on EDP")
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: <stable@vger.kernel.org> # v4.17+
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107489
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105338Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Tested-by: NAlexander Wilson <alexander.wilson@ncf.edu>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181009212804.702-1-manasi.d.navare@intel.com

Clarifies the clock recovery loop limit comment that 80
max_cr_tries for pre-DP1.4 devices was chosen as a very
tolerant upper bound.
Assumptions made:
- DP1.4 syncs should be smarter so they won't need more
than 10 tries
- pre-DP1.4 syncs should be compliant enough to not need
that many tries (80) but we should tolerate any that may
trigger this corner case

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Marc Herbert <marc.herbert@intel.com>
Suggested-by: NMarc Herbert <marc.herbert@intel.com>
Signed-off-by: NNathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Reviewed-by: NMarc Herbert <marc.herbert@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1532471612-30001-1-git-send-email-nathan.d.ciobanu@linux.intel.com

Changes the type and renames the max_vswing_tries variable
which was declared as an integer but used as a boolean
making it easy to be confused with a counter.

Changes in v2:
    - updated the title and commit message
    - left the loop exit point in place

v3: fix typo in title
v4: renamed max_vswing to max_vswing_reached (Ville)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Marc Herbert <marc.herbert@intel.com>
Signed-off-by: NNathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180720214413.29506-2-rodrigo.vivi@intel.com

Limit the link training clock recovery loop to 10 attempts at
LANEx_CR_DONE per DP 1.4 spec section 3.5.1.2.2 and 80 attempts for
pre-DP 1.4 (4 voltage levels x 4 preemphasis levels x
x 5 identical voltages tries). Some faulty USB-C MST hubs can
cause us to get stuck in this loop indefinitely requesting something
like:

    voltage swing: 0, pre-emphasis level: 2
    voltage swing: 1, pre-emphasis level: 2
    voltage swing: 0, pre-emphasis level: 3

over and over so max_vswing would never be reached,
drm_dp_clock_recovery_ok() would never return true and voltage_tries
would always get reset to 1. The driver sends those values to the hub
but the hub keeps requesting new values every time.

Changes in v2:
    - updated commit message (DK, Manasi)
    - defined DP_DP14_MAX_CR_TRIES (Marc)
    - made the loop iterate for max 10 times (Rodrigo, Marc)

Changes in v3:
    - changed error message to use DP_DP14_MAX_CR_TRIES

Changes in v4:
    - Updated the title to reflect the change
    - Updated the commit message
    - Added 80 attempts for pre-DP 1.4 devices

Changes in v5:
    - Removed DP_DP14_MAX_CR_TRIES from drm

v6: Updated comment to match kernel style (Rodrigo)

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Marc Herbert <marc.herbert@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NNathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180720214413.29506-1-rodrigo.vivi@intel.com

DP spec 1.4 supports training pattern set 4 (TPS4) for HBR3 link
rate. This will be used in link training's channel equalization
phase if supported by both source and sink.
This patch adds the helpers to check if HBR3 is supported and uses
TPS4 in training pattern selection during link training.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: NJames Ausmus <james.ausmus@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180611222655.5696-2-paulo.r.zanoni@intel.com

We call intel_dp_compute_rate() in intel_dp_compute_config() only to be
able to debug log the link_bw and rate_select parameters; we don't use
the parameters here for anything else. We call intel_dp_compute_rate()
again during link training where we actually need and use the
parameters.

Move the debug logging of link_bw and rate_select to
intel_dp_link_training_clock_recovery(), and clean up the extra
intel_dp_compute_rate() call and extra clutter from the already
overcrowded intel_dp_compute_config().

v2: Rewrote commit message (Rodrigo, Manasi)
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c5cf6a179e2d244eceb6bb80a792765d9efbee4f.1524730974.git.jani.nikula@intel.com

LSPCON likes to throw short HPDs during the enable seqeunce prior to the
link being trained. These obviously result in the channel CR/EQ check
failing and thus we schedule a pointless hotplug work to retrain the
link. Avoid that by ignoring the bad CR/EQ status until we've actually
initially trained the link.

I've not actually investigated to see what LSPCON is trying to signal
with the short pulse. But as long as it signals anything I think we're
supposed to check the link status anyway, so I don't really see other
good ways to solve this. I've not seen these short pulses being
generated by normal DP sinks.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Signed-off-by: NLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180117192149.17760-5-ville.syrjala@linux.intel.com

intel_dp->channel_eq_status is used in exactly one function, and we
don't need it to persist between calls. So just go back to using a
local variable instead.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NLyude Paul <lyude@redhat.com>
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180117192149.17760-4-ville.syrjala@linux.intel.com

In case of eDP because the panel has a fixed mode, the link rate
and lane count at which it is trained corresponds to the link BW
required to support the native resolution of the panel. In case of
panles with lower resolutions where fewer lanes are hooked up internally,
that number is reflected in the MAX_LANE_COUNT DPCD register of the panel.
So it is pointless to fallback to lower link rate/lane count in case
of link training failure on eDP connector since the lower link BW
will not support the native resolution of the panel and we cannot
prune the preferred mode on the eDP connector.

In case of Link training failure on the eDP panel, something is wrong
in the HW internally and hence driver errors out with a loud
and clear DRM_ERROR message.

v2:
* Fix the DEBUG_ERROR and add {} in else (Ville Syrjala)

Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NVille Syrjala <ville.syrjala@linux.intel.com>
Reference: https://bugs.freedesktop.org/show_bug.cgi?id=103369Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1507835618-23051-1-git-send-email-manasi.d.navare@intel.com
(cherry picked from commit c0cfb10d)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

In case of eDP because the panel has a fixed mode, the link rate
and lane count at which it is trained corresponds to the link BW
required to support the native resolution of the panel. In case of
panles with lower resolutions where fewer lanes are hooked up internally,
that number is reflected in the MAX_LANE_COUNT DPCD register of the panel.
So it is pointless to fallback to lower link rate/lane count in case
of link training failure on eDP connector since the lower link BW
will not support the native resolution of the panel and we cannot
prune the preferred mode on the eDP connector.

In case of Link training failure on the eDP panel, something is wrong
in the HW internally and hence driver errors out with a loud
and clear DRM_ERROR message.

v2:
* Fix the DEBUG_ERROR and add {} in else (Ville Syrjala)

Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NVille Syrjala <ville.syrjala@linux.intel.com>
Reference: https://bugs.freedesktop.org/show_bug.cgi?id=103369Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1507835618-23051-1-git-send-email-manasi.d.navare@intel.com

This adds the connector name when printing a debug message about the DP
link training result. It is useful to figure out what connector is
failing when multiple DP connectors are used.
Signed-off-by: NPaul Kocialkowski <paul.kocialkowski@linux.intel.com>
Reviewed-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170718142536.2306-1-paul.kocialkowski@linux.intel.com

If link training at a link rate optimal for a particular
mode fails during modeset's atomic commit phase, then we
let the modeset complete and then retry. We save the link rate
value at which link training failed, update the link status property
to "BAD" and use a lower link rate to prune the modes. It will redo
the modeset on the current mode at lower link rate or if the current
mode gets pruned due to lower link constraints then, it will send a
hotplug uevent for userspace to handle it.

This is also required to pass DP CTS tests 4.3.1.3, 4.3.1.4,
4.3.1.6.

This patch is a resend of the original commit id (233ce881
"drm/i915: Implement Link Rate fallback on Link training failure")
which got reverted in this commit id (afc1ebf4 Revert
"drm/i915: Implement Link Rate fallback on Link training failure")
due to CI failures.

After investigating the CI failures it was found that these
were essentially the failures which were always there but hidden because
they used to be DRM_DEBUG_KMS messages for link failures so never got
caught by CI. But now this patch actually throws DRM_ERROR if the link
training fails at RBR and 1 lane. So it caught these link train failures.

There were two failures:
1. On SKL 6700k this was because the machine in CI lab is a SKL desktop
without eDP on Port A. But our VBT initialization code in the driver writes
VBT defaults in a way that it always sets DP flag on Port A and this does
not get cleared after parsing the VBT outputs. This has been fixed in
commit id (bb1d1329 "drm/i915/vbt: split out defaults that are set
when there is no VBT) and (66578857 "drm/i915/vbt: don't propagate
errors from intel_bios_init())

2. On ILK-650 desktop - This was happening because of a bad monitor desktop
combination. I switched the monitor in the CI lab and that helped get rid
of the link failures on ILK system.

v10:
* Rebase on drm-tip and resend after revert
v9:
* Use the trimmed max values of link rate/lane count based on
link train fallback (Daniel Vetter)
v8:
* Set link_status to BAD first and then call mode_valid (Jani Nikula)
v7:
Remove the redundant variable in previous patch itself
v6:
* Obtain link rate index from fallback_link_rate using
the helper intel_dp_link_rate_index (Jani Nikula)
* Include fallback within intel_dp_start_link_train (Jani Nikula)
v5:
* Move set link status to drm core (Daniel Vetter, Jani Nikula)
v4:
* Add fallback support for non DDI platforms too
* Set connector->link status inside set_link_status function
(Jani Nikula)
v3:
* Set link status property to BAd unconditionally (Jani Nikula)
* Dont use two separate variables link_train_failed and link_status
to indicate same thing (Jani Nikula)
v2:
* Squashed a few patches (Jani Nikula)
Acked-by: NTony Cheng <tony.cheng@amd.com>
Acked-by: NHarry Wentland <Harry.wentland@amd.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/16ca48b1e74c618929245e9a085b9e3483c3a16d.1491485983.git.jani.nikula@intel.com

There is some conflation related to sink rates, making this change more
complicated than it would otherwise have to be. There are three changes
here that are rather difficult to split up:

1) Use the intel_dp->sink_rates array for all DP, not just eDP 1.4. We
   initialize it from DPCD on eDP 1.4 like before, but generate it based
   on DP_MAX_LINK_RATE on others. This reduces code complexity when we
   need to use the sink rates; they are all always in the sink_rates
   array.

2) Update the sink rate array whenever we read DPCD, and use the
   information from there. This increases code readability when we need
   the sink rates.

3) Disentangle fallback rate limiting from sink rates. In the code, the
   max rate is a dynamic property of the *link*, not of the *sink*. Do
   the limiting after intersecting the source and sink rates, which are
   static properties of the devices.

This paves the way for follow-up refactoring that I've refrained from
doing here to keep this change as simple as it possibly can.

v2: introduce use_rate_select and handle non-confirming eDP (Ville)

v3: don't clobber cached eDP rates on short pulse (Ville)

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/071bad76467f8ab2e73f3f61ad52d5a468004c71.1490712890.git.jani.nikula@intel.com

This reverts commit 233ce881.

I assumed it's ok, but really should have double-checked - CI caught
tons of fail :(

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Acked-by: NManasi Navare <manasi.d.navare@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170301171749.13053-1-daniel.vetter@ffwll.ch

If link training at a link rate optimal for a particular
mode fails during modeset's atomic commit phase, then we
let the modeset complete and then retry. We save the link rate
value at which link training failed, update the link status property
to "BAD" and use a lower link rate to prune the modes. It will redo
the modeset on the current mode at lower link rate or if the current
mode gets pruned due to lower link constraints then, it will send a
hotplug uevent for userspace to handle it.

This is also required to pass DP CTS tests 4.3.1.3, 4.3.1.4,
4.3.1.6.

v9:
* Use the trimmed max values of link rate/lane count based on
link train fallback (Daniel Vetter)
v8:
* Set link_status to BAD first and then call mode_valid (Jani Nikula)
v7:
Remove the redundant variable in previous patch itself
v6:
* Obtain link rate index from fallback_link_rate using
the helper intel_dp_link_rate_index (Jani Nikula)
* Include fallback within intel_dp_start_link_train (Jani Nikula)
v5:
* Move set link status to drm core (Daniel Vetter, Jani Nikula)
v4:
* Add fallback support for non DDI platforms too
* Set connector->link status inside set_link_status function
(Jani Nikula)
v3:
* Set link status property to BAd unconditionally (Jani Nikula)
* Dont use two separate variables link_train_failed and link_status
to indicate same thing (Jani Nikula)
v2:
* Squashed a few patches (Jani Nikula)
Acked-by: NTony Cheng <tony.cheng@amd.com>
Acked-by: NHarry Wentland <Harry.wentland@amd.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/d796cc0c2814d668a47ef43c464f9a4089d46d64.1481883920.git.jani.nikula@intel.com

Pre-production hardware is not supported.
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/7929af62a68504c84038a8db1625bd96ebaa9e6f.1474034059.git.jani.nikula@intel.com

Fix the number of tries in channel euqalization link training sequence
according to DP 1.2 Spec. It returns a boolean depending on channel
equalization pass or failure.
Signed-off-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

This function cleans up clock recovery loop in link training compliant
tp Dp Spec 1.2. It tries the clock recovery 5 times for the same voltage
or until max voltage swing is reached and removes the additional non
compliant retries. This function now returns a boolean values based on
if clock recovery passed or failed.

v3:
* Better Debug prints in case of failures (Mika Kahola)
v2:
* Rebased on top of new revision of vswing patch (Manasi Navare)
Signed-off-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

Wrap the max. vswing check in a separate function.
This makes the clock recovery phase of DP link training cleaner

v3:
Fixed the paranthesis warning (Mika Kahola)
v2:
Fixed the Compiler warning (Mika Kahola)
Signed-off-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: NManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

A full dump of link status can be handy in debugging link training
failures. Let's add that to the debug messages when link training fails.

v2: Removing unrelated clean up (Jani)
Signed-off-by: NDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470343716-5574-3-git-send-email-dhinakaran.pandiyan@intel.com

It has been found out that in some HW combination the DisplayPort
fast link training feature caused screen flickering. Let's revert
this feature for now until we can ensure that the feature works for
all platforms.

This is a manual revert of commits 5fa836a9 ("drm/i915: DP link
training optimization") and 4e96c977 ("drm/i915: eDP link training
optimization").

Fixes: 5fa836a9 ("drm/i915: DP link training optimization")
Fixes: 4e96c977 ("drm/i915: eDP link training optimization")
Cc: <stable@vger.kernel.org> # v4.2+

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91393Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466410226-19543-1-git-send-email-mika.kahola@intel.com
(cherry picked from commit 91df09d9)

It has been found out that in some HW combination the DisplayPort
fast link training feature caused screen flickering. Let's revert
this feature for now until we can ensure that the feature works for
all platforms.

This is a manual revert of commits 5fa836a9 ("drm/i915: DP link
training optimization") and 4e96c977 ("drm/i915: eDP link training
optimization").

Fixes: 5fa836a9 ("drm/i915: DP link training optimization")
Fixes: 4e96c977 ("drm/i915: eDP link training optimization")
Cc: <stable@vger.kernel.org> # v4.2+

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91393Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NMika Kahola <mika.kahola@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466410226-19543-1-git-send-email-mika.kahola@intel.com