[ Upstream commit 7b4d8db657192066bc6f1f6635d348413dac1e18 ]
The sequence for Source DP PHY CTS automation is [2][1]:
1- Emulate successful Link Training(LT)
2- Short HPD and change link rates and number of lanes by LT.
(This is same flow for Link Layer CTS)
3- Short HPD and change PHY test pattern and swing/pre-emphasis
levels (This step should not trigger LT)
The problem is with DP PHY compliance setup as follow:
[DPTX + on board LTTPR]------Main Link--->[Scope]
^ |
| |
| |
----------Aux Ch------>[Aux Emulator]
At step 3, before writing TRAINING_LANEx_SET/LINK_QUAL_PATTERN_SET
to declare the pattern/swing requested by scope, we write link
config in LINK_BW_SET/LANE_COUNT_SET on a port that has LTTPR.
As LTTPR snoops aux transaction, LINK_BW_SET/LANE_COUNT_SET writes
indicate a LT will start [Check DP 2.0 E11 -Sec 3.6.8.2 & 3.6.8.6.3],
and LTTPR will reset the link and stop sending DP signals to
DPTX/Scope causing the measurements to fail. Note that step 3 will
not trigger LT and DP link will never recovered by the
Aux Emulator/Scope.
The reset of link can be tested with a monitor connected to LTTPR
port simply by writing to LINK_BW_SET or LANE_COUNT_SET as follow
igt/tools/dpcd_reg write --offset=0x100 --value 0x14 --device=2
OR
printf '\x14' | sudo dd of=/dev/drm_dp_aux2 bs=1 count=1 conv=notrunc
seek=$((0x100))
This single aux write causes the screen to blank, sending short HPD to
DPTX, setting LINK_STATUS_UPDATE = 1 in DPCD 0x204, and triggering LT.
As stated in [1]:
"Before any TX electrical testing can be performed, the link between a
DPTX and DPRX (in this case, a piece of test equipment), including all
LTTPRs within the path, shall be trained as defined in this Standard."
In addition, changing Phy pattern/Swing/Pre-emphasis (Step 3) uses the
same link rate and lane count applied on step 2, so no need to redo LT.
The fix is to not rewrite link config in step 3, and just writes
TRAINING_LANEx_SET and LINK_QUAL_PATTERN_SET
[1]: DP 2.0 E11 - 3.6.11.1 LTTPR DPTX_PHY Electrical Compliance
[2]: Configuring UnigrafDPTC Controller - Automation Test Sequence
https://www.keysight.com/us/en/assets/9922-01244/help-files/
D9040DPPC-DisplayPort-Test-Software-Online-Help-latest.chm
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Or Cochvi <or.cochvi@intel.com>
Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220916054900.415804-1-khaled.almahallawy@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Since DP 1.3, it's been possible for DP receivers to specify an
additional set of DPCD capabilities, which can take precedence over the
capabilities reported at DP_DPCD_REV.
Basically any device supporting DP is going to need to read these in an
identical manner, in particular nouveau, so let's go ahead and just move
this code out of i915 into a shared DRM DP helper that we can use in
other drivers.
v2:
* Remove redundant dpcd[DP_DPCD_REV] == 0 check
* Fix drm_dp_dpcd_read() ret checks
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-20-lyude@redhat.com
And of course, we'll also need to read the sink count from other drivers
as well if we're checking whether or not it's supported. So, let's
extract the code for this into another helper.
v2:
* Fix drm_dp_dpcd_readb() ret check
* Add back comment and move back sink_count assignment in intel_dp_get_dpcd()
v5:
* Change name from drm_dp_get_sink_count() to drm_dp_read_sink_count()
* Also, add "See also:" section to kdocs
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-17-lyude@redhat.com
Since other drivers are also going to need to be aware of the sink count
in order to do proper dongle detection, we might as well steal i915's
DP_SINK_COUNT helpers and move them into DRM helpers so that other
dirvers can use them as well.
Note that this also starts using intel_dp_has_sink_count() in
intel_dp_detect_dpcd(), which is a functional change.
v5:
* Change name from drm_dp_has_sink_count() to
drm_dp_read_sink_count_cap()
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-16-lyude@redhat.com
We're going to be doing the same probing process in nouveau for
determining downstream DP port capabilities, so let's deduplicate the
work by moving i915's code for handling this into a shared helper:
drm_dp_read_downstream_info().
Note that when we do this, we also do make some functional changes while
we're at it:
* We always clear the downstream port info before trying to read it,
just to make things easier for the caller
* We skip reading downstream port info if the DPCD indicates that we
don't support downstream port info
* We only read as many bytes as needed for the reported number of
downstream ports, no sense in reading the whole thing every time
v2:
* Fixup logic for calculating the downstream port length to account for
the fact that downstream port caps can be either 1 byte or 4 bytes
long. We can actually skip fixing the max_clock/max_bpc helpers here
since they all check for DP_DETAILED_CAP_INFO_AVAILABLE anyway.
* Fix ret code check for drm_dp_dpcd_read
v5:
* Change name from drm_dp_downstream_read_info() to
drm_dp_read_downstream_info()
* Also, add "See Also" sections for the various downstream info
functions (drm_dp_read_downstream_info(), drm_dp_downstream_max_clock(),
drm_dp_downstream_max_bpc())
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-14-lyude@redhat.com
Currently, downstream port type is only reported in debugfs. This
information should be considered important since it reflects the actual
physical connector type. Some userspace (e.g. window compositors)
may want to show this info to a user.
The 'subconnector' property is already utilized for DVI-I and TV-out for
reporting connector subtype.
The initial motivation for this feature came from i2c test [1].
It is supposed to be skipped on VGA connectors, but it cannot
detect VGA over DP and fails instead.
v2:
- Ville: utilized drm_dp_is_branch()
- Ville: implement DP 1.0 downstream type info
- Replaced create_dp_properties with add_dp_subconnector_property
- Added dp_set_subconnector_property helper
v4:
- Ville: add DP1.0 best assumption about subconnector
- Ville: assume DVI is DVI-D
- Ville: reuse Writeback enum value for Virtual subconnector
- Renamed #defines: HDMI -> HDMIA, DP -> DisplayPort
v5: rebase
v6:
- Jani Nikula: renamed a function name
- Jani Nikula: addressed the issues with documentation
[1]: https://bugs.freedesktop.org/show_bug.cgi?id=104097
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-1-git-send-email-jeevan.b@intel.com
drm-misc-next for v5.9:
UAPI Changes:
- Add DRM_MODE_TYPE_USERDEF for video modes specified in cmdline.
Cross-subsystem Changes:
- Assorted devicetree binding updates.
- Add might_sleep() to dma_fence_wait().
- Fix fbdev's get_user_pages_fast() handling, and use pin_user_pages.
- Small cleanup with IS_BUILTIN in video/fbdev drivers.
- Fix video/hdmi coding style for infoframe size.
Core Changes:
- Silence vblank output during init.
- Fix DP-MST corruption during send msg timeout.
- Clear leak in drm_gem_objecs_lookup().
- Make newlines work with force connector attribute.
- Fix module refcounting error in drm_encoder_slave, and use new i2c api.
- Header fix for drm_managed.c
- More struct_mutex removal for !legacy drivers:
- Remove gem_free_object()
- Removal of drm_gem_object_put_unlocked().
- Show current->comm alongside pid in debug printfs.
- Add drm_client_modeset_check() + drm_client_framebuffer_flush().
- Replace drm_fb_swab16 with drm_fb_swap that also supports 32-bits.
- Remove mode->vrefresh, and compactify drm_display_mode.
- Use drm_* macros for logging and warnings.
- Add WARN when drm_gem_get_pages is used on a private obj.
- Handle importing and imported dmabuf better in shmem helpers.
- Small fix for drm/mm hole size comparison, and remove invalid entry optimization.
- Add a drm/mm selftest.
- Set DSI connector type for DSI panels.
- Assorted small fixes and documentation updates.
- Fix DDI I2C device registration for MST ports, and flushing on destroy.
- Fix master_set return type, used by vmwgfx.
- Make the drm_set/drop_master ioctl symmetrical.
Driver Changes:
Allow iommu in the sun4i driver and use it for sun8i.
- Simplify backlight lookup for omap, amba-clcd and tilcdc.
- Hold reg_lock for rockchip.
- Add support for bridge gpio and lane reordering + polarity to ti-sn65dsi86, and fix clock choice.
- Small assorted fixes to tilcdc, vc4, i915, omap, fbdev/sm712fb, fbdev/pxafb, console/newport_con, msm, virtio, udl, malidp, hdlcd, bridge/ti-sn65dsi86, panfrost.
- Remove hw cursor support for mgag200, and use simple kms helper + shmem helpers.
- Add support for KOE Allow iommu in the sun4i driver and use it for sun8i.
- Simplify backlight lookup for omap, amba-clcd and tilcdc.
- Hold reg_lock for rockchip.
- Add support for bridge gpio and lane reordering + polarity to ti-sn65dsi86, and fix clock choice.
- Small assorted fixes to tilcdc, vc4 (multiple), i915.
- Remove hw cursor support for mgag200, and use simple kms helper + shmem helpers.
- Add support for KOE TX26D202VM0BWA panel.
- Use GEM CMA functions in arc, arm, atmel-hlcdc, fsi-dcu, hisilicon, imx, ingenic, komeda, malidp, mcde, meson, msxfb, rcar-du, shmobile, stm, sti, tilcdc, tve200, zte.
- Remove gem_print_info.
- Improve gem_create_object_helper so udl can use shmem helpers.
- Convert vc4 dt bindings to schemas, and add clock properties.
- Device initialization cleanups for mgag200.
- Add a workaround to fix DP-MST short pulses handling on broken hardware in i915.
- Allow build test compiling arm drivers.
- Use managed pci functions in mgag200 and ast.
- Use dev_groups in malidp.
- Add per pixel alpha support for PX30 VOP in rockchip.
- Silence deferred probe logs in panfrost.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/001cd9a6-405d-4e29-43d8-354f53ae4e8b@linux.intel.com
During phy compliance auto test mode source need to read
requested test pattern from sink through DPCD. After processing
the request source need to set the pattern. So set/get method
added in drm layer as it is DP protocol.
v2: As per review feedback from Manasi on RFC version,
- added dp revision as function argument in set_phy_pattern api.
- used int for link_rate and u8 for lane_count to align with existing code.
v3: As per review feedback from Harry,
- used sizeof() instead of magic number.
- corrected kernel-doc for drm_dp_phy_test_params structure.
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200316103759.12867-3-animesh.manna@intel.com
UAPI Changes:
On i915 we have a new UAPI to allow userspace to specify CS ring buffer size on
construction (I915_CONTEXT_PARAM_RINGSIZE) and also new sysfs entries exposing
various engine properties
GVT Changes:
VFIO edid getting expanded to all platforms and a big cleanup around attr
group, unused vblank complete, kvmgt, Intel engine and dev_priv usages.
i915 Changes:
- new UAPI to allow userspace to specify CS ring buffer size on construction
(I915_CONTEXT_PARAM_RINGSIZE) - (Chris)
- New sysfs entries exposing various engine properties (Chris)
- Tiger Lake is out of require_force_probe protection (Jose)
- Changes in many places around active requests, reset and heartbeat (Chris)
- Stop assigning drm-dev_private pointer (Jani)
- Many code refactor in many places, including intel_modeset_init,
increasing use of intel_uncore_*, vgpu, and gvt stuff (Jani)
- Fixes around display pipe iterators (Anshuman)
- Tigerlake enabling work (Matt Ropper, Matt Atwood, Ville, Lucas, Daniele,
Jose, Anusha, Vivek, Swathi, Caz. Kai)
- Code clean-up like reducing use of drm/i915_drv.h, removing unused
registers, removing garbage warns, and some other code polishing (Jani, Lucas,
Ville)
- Selftests fixes, improvements and additions (Chris, Dan, Aditya, Matt Auld)
- Fix plane possible_crtcs bit mask (Anshuman)
- Fixes and cleanup on GLK pre production identification and w/a (Ville)
- Fix display orientation on few cases (Hans, Ville)
- dbuf clean-up and improvements for slice arrays handling (Ville)
- Improvement around min cdclk calculation (Stanislav)
- Fixes and refactor around display PLLs (Imre)
- Other execlists and perf fixes (Chris)
- Documentation fixes (Jani, Chris)
- Fix build issue (Anshuman)
- Many more fixes around the locking mechanisms (Chris)
- Other fixes and debugability info around preemption (Chris, Tvrtko)
- Add mechanism to submit a context WA on ring submission (Mika)
- Clear all Eu/L3 resitual context (Prathap)
- More changes around local memory (Abdiel, Matt, Chris)
- Fix RPS (Chris)
- DP MST fix (Lyude)
- Display FBC fixes (Jose, RK)
- debugfs cleanup (Tvrtko)
- More convertion towards drm_debive based loggin (Wambui, Ram)
- Avoid potential buffer overflow (Takashi)
- Ice Lake and Elkhart Lake workarounds (Matt Roper)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200314001535.GA2969344@intel.com
This fixes a problem found on the MacBookPro 2017 Retina panel.
The panel reports 10 bpc color depth in its EDID, and the
firmware chooses link settings at boot which support enough
bandwidth for 10 bpc (324000 kbit/sec = multiplier 0xc),
but the DP_MAX_LINK_RATE dpcd register only reports
2.7 Gbps (multiplier value 0xa) as possible, in direct
contradiction of what the firmware successfully set up.
This restricts the panel to 8 bpc, not providing the full
color depth of the panel.
This patch adds a quirk specific to the MBP 2017 15" Retina
panel to add the additiional 324000 kbps link rate during
edp setup.
Link to previous discussion of a different attempted fix
with Ville and Jani:
https://patchwork.kernel.org/patch/11325935/
v2: Follow Jani's proposal of defining quirk_rates[] instead
of just appending 324000. This for better clarity.
v3: Rebased onto current drm-tip, as of 16-March-2020. Adapt
to new edid_quirks parameter of drm_dp_has_quirk().
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200316042340.4783-1-mario.kleiner.de@gmail.com
According to Dell, trying to match their panels via OUI is not reliable
enough and we've been told that we should check against the EDID
instead. As well, Dell seems to have some panels that are actually
intended to switch between using PWM for backlight controls and DPCD for
backlight controls depending on whether or not the panel is in HDR or
SDR mode. Yikes.
Regardless, we need to add quirks for these so that DPCD backlight
controls get enabled by default, since without additional driver support
that's the only form of brightness control that will work. Hopefully in
the future we can remove these quirks once we have a better way of
probing for this.
Changes since v1:
* Add one more EDID per Dell's request
* Remove model number (which is possibly wrong) and replace with Dell
CML 2020 systems
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211183358.157448-4-lyude@redhat.com
Reviewed-by: Adam Jackson <ajax@redhat.com>
The X1 Extreme is one of the systems that lies about which backlight
interface that it uses in its VBIOS as PWM backlight controls don't work
at all on this machine. It's possible that this panel could be one of
the infamous ones that can switch between PWM mode and DPCD backlight
control mode, but we haven't gotten any more details on this from Lenovo
just yet. For the time being though, making sure the backlight 'just
works' is a bit more important.
So, add a quirk to force DPCD backlight controls on for these systems
based on EDID (since this panel doesn't appear to fill in the device ID).
Hopefully in the future we'll figure out a better way of probing this.
Changes since v2:
* The bugzilla URL is deprecated, bug reporting happens on gitlab now.
Update the messages we print to reflect this
* Also, take the opportunity to move FDO_BUG_URL out of i915_utils.c and
into i915_utils.h so that other places which print things that aren't
traditional errors but are worth filing bugs about, can actually use
it.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200303215320.93491-1-lyude@redhat.com
The whole point of using OUIs is so that we can recognize certain
devices and potentially apply quirks for them. Normally this should work
quite well, but there appears to be quite a number of laptop panels out
there that will fill the OUI but not the device ID. As such, for devices
like this I can't imagine it's a very good idea to try relying on OUIs
for applying quirks. As well, some laptop vendors have confirmed to us
that their panels have this exact issue.
So, let's introduce the ability to apply DP quirks based on EDID
identification. We reuse the same quirk bits for OUI-based quirks, so
that callers can simply check all possible quirks using
drm_dp_has_quirk().
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211183358.157448-2-lyude@redhat.com
drm-misc-next for 5.7:
UAPI Changes:
- lima: Add support for heap buffers
Cross-subsystem Changes:
Core Changes:
- Implement mode_config mode_valid for memory constrained drivers
- Bus format negociation between bridges
- Consolidate fake vblank events for drivers without vblank interrupts
- drm/bufs: dma_alloc related cleanups
- drm/dp_mst: Various fixes
- drm/print: New drm_device based print helpers
- Thomas is a drm-misc maintainer now!
Driver Changes:
- DPMS cleanups for atomic drivers
- Removal of owner field in SPI tinydrm drivers
- Removal of explicit dependency on DT for tinydrm drivers
- Conversion to YAML schemas for DT bindings
- tidss: New driver
- virtio: various reworks and fixes
- Our usual dozen or so new panels or bridges
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200210093421.xu4sofldm6wm6xq6@gilmour.lan
Lyude needs some patches in 5.6-rc2 and we didn't bring drm-misc-next
forward yet, so it looks like a good occasion.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Unlike DP 1.2 edid corruption test, DP 1.4 requires to calculate
real CRC value of the last edid data block, and write it back.
Current edid CRC calculates routine adds the last CRC byte,
and check if non-zero.
This behavior is not accurate; actually, we need to return
the actual CRC value when corruption is detected.
This commit changes this issue by returning the calculated CRC,
and initiate the required sequence.
Change since v7
- Fix for CI.CHECKPATCH
Change since v6
- Add return check
Change since v5
- Obtain real CRC value before dumping bad edid
Change since v4
- Fix for CI.CHECKPATCH
Change since v3
- Fix a minor typo.
Change since v2
- Rewrite checksum computation routine to avoid duplicated code.
- Rename to avoid confusion.
Change since v1
- Have separate routine for returning real CRC.
Signed-off-by: Jerry (Fangzhi) Zuo <Jerry.Zuo@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211160832.24259-1-Jerry.Zuo@amd.com
[why]
We need to minimally initialize the remote aux channel, e.g. the
crc work struct of remote aux to dump the sink's DPRX CRCs in MST
setup.
[how]
Add helper that only initializes the crc work struct of the remote
aux, hooke crc work queue to 'drm_dp_aux_crc_work'. Then call this
helper in DP MST port initialization.
This, plus David Francis' patch [1], fix the issue of MST remote
aux DPCD CRCs read.
[1] https://patchwork.kernel.org/patch/11217941/
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: David (Dingchen) Zhang <dingchen.zhang@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Synaptics DP1.4 hubs (BRANCH_ID 0x90CC24) do not
support virtual DPCD registers, but do support DSC.
The DSC caps can be read from the physical aux,
like in SST DSC. These hubs have many different
DEVICE_IDs. Add a new quirk to detect this case.
v2: Fix error when checking return of drm_dp_read_desc
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Instead of having drm_dp_dpcd_read/write and
drm_dp_mst_dpcd_read/write as entry points into the
aux code, have drm_dp_dpcd_read/write handle both.
This means that DRM drivers can make MST DPCD read/writes.
v2: Fix spacing
v3: Dump dpcd access on MST read/writes
v4: Fix calling wrong function on DPCD write
v5: delete deprecated include of drmP.h
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: David Francis <David.Francis@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
During the discussion of patches that enhance the drm_dp_link helpers it
was concluded that these helpers aren't very useful to begin with. After
all other drivers have been converted not to use these helpers anymore,
move these helpers into the last remaining user: Tegra DRM.
If at some point these helpers are deemed more widely useful, they can
be moved out into the DRM DP helpers again.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021143437.1477719-14-thierry.reding@gmail.com
Use microsecond sleeps for the clock recovery and channel equalization
delays during link training. The duration of these delays can be from
100 us up to 16 ms. It is rude to busy-loop for that amount of time.
While at it, also convert to standard coding style by putting the
opening braces in a function definition on a new line. Also switch to
using an unsigned int for the AUX read interval to match the data type
of the parameters to usleep_range().
v2: use correct multiplier for training delays (Philipp Zabel)
v3: clarify data type change in commit message
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021143437.1477719-7-thierry.reding@gmail.com
Although the DisplayPort spec explicitly calls out the 1.62/2.7/5.4/8.1
link rates, the value of LINK_BW_SET is calculated. The DisplayPort
spec says "Main-Link Bandwidth Setting = Value x 0.27Gbps/lane".
A bridge that we're looking to upstream uses 6.75Gbps rate (value 0x19)
[1], and that precludes it from using these functions.
This 6.75Gbps rate is defined in the spec as (credit to Ville for posting this):
A MyDP Source device, upon reading the MAX_LINK_RATE register of the
downstream DPRX programmed to 19h (which can be the case only for a
MyDP-to-Legacy or MyDP-to-DP lane count converter) can program the
LINK_BW_SET register (DPCD Address 00100h) to 19h to enable 6.75Gbps/lane."
So to avoid failing on legitimate rates in the future, this patch calculates thevalues according to spec instead of restricting these values to one of the
DP_LINK_BW_* #defines.
No functional change for the well-defined values, but we lose the
warning (and return the correct value) for ill-defined bw values.
Signed-off-by: Sean Paul <seanpaul@chromium.org>
[1] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1689251/2/drivers/gpu/drm/bridge/analogix/anx7625.c#636
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717160148.256826-1-sean@poorly.run
