[WD19TB] external DP failed with DRM error message

[Hsuan-Yu Lin]

[SRU Justfication]

TGL platform can't output external monitor on WD19TB docking.
There's no screen on the external monitor.
error in dmesg:

[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underru

[Fix]
According to Intel's suggestion,
we need this: https://patchwork.freedesktop.org/series/78909/
Also for dependency, the following patches are landed in drm-tip
and necessary for support TGL platform:

* commit f4ece33f51d8 ("drm/i915/tgl+: Fix TBT DPLL fractional divider for 38.4MHz ref clock")
* commit a6e96d6948c8 ("drm/i915/tgl+: Use the correct DP_TP_* register instances in MST encoders")
* commit f822a79734e1 ("drm/i915/dc3co: Avoid full modeset when EXITLINE needs to be changed")
* commit 1a7e82efaa8a ("drm/i915/tgl: Add HBR and HBR2+ voltage swing table")
* commit 80907edcc6ed ("UBUNTU: SAUCE: drm/i915/bios: add intel_bios_hdmi_level_shift()")
* commit 6df896896c8d ("drm/i915/tgl: Implement WA_16011163337")
* commit cb730fe971f0 ("drm/i915/tgl: Update TC DP vswing table")

[Test]
The WD19TB can output HDMI/DP to external monitor.

[Regression Potential]
Medium, in order to support TGL platform, we also include two patches:
drm/i915/bios: add intel_bios_hdmi_level_shift()
drm/i915/dc3co: Avoid full modeset when EXITLINE needs to be changed
The two patches are not related to TGL, but for dependency.

[Hsuan-Yu Lin (shanelin)]

https://lists.ubuntu.com/archives/kernel-team/2020-July/111754.html

[Hsuan-Yu Lin (shanelin)]

Testing PPA:
https://launchpad.net/~shanelin/+archive/ubuntu/lp1886165

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Hsuan-Yu Lin (shanelin)]

Verification on TGL machine PASSED (10/10)

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-oem-5.6 - 5.6.0-1020.20

---------------
linux-oem-5.6 (5.6.0-1020.20) focal; urgency=medium

  * focal/linux-oem-5.6: 5.6.0-1020.20 -proposed tracker (LP: #1886753)

  * Realtek [10ec:c82f] Subsystem [17aa:c02f] Wifi adapter not found
    (LP: #1886247)
    - SAUCE: rtw88: 8822ce: add support for device ID 0xc82f

  * [WD19TB] external DP failed with DRM error message (LP: #1886165)
    - drm/i915/tgl: Update TC DP vswing table
    - drm/i915/tgl: Implement WA_16011163337
    - SAUCE: drm/i915/bios: add intel_bios_hdmi_level_shift()
    - drm/i915/tgl: Add HBR and HBR2+ voltage swing table
    - drm/i915/dc3co: Avoid full modeset when EXITLINE needs to be changed
    - drm/i915/tgl+: Use the correct DP_TP_* register instances in MST encoders
    - drm/i915/tgl+: Fix TBT DPLL fractional divider for 38.4MHz ref clock

  * ubuntu_aufs_smoke_test failed on Focal OEM 5.6 (LP: #1879308)
    - SAUCE: fs: Enable aufs

 -- Timo Aaltonen <email address hidden> Wed, 08 Jul 2020 11:44:53 +0300

[AceLan Kao (acelankao)]

below commits are in v5.9-rc1, we have to backport those commits to groovy.

09eac8277262 drm/i915/tgl+: Fix TBT DPLL fractional divider for 38.4MHz ref clock
f153478de4b2 drm/i915/tgl+: Use the correct DP_TP_* register instances in MST encoders
9fa6769952ee drm/i915/tgl: Add HBR and HBR2+ voltage swing table
84f9cbf33580 drm/i915/tgl: Implement WA_16011163337
250a353cd85f drm/i915/tgl: Update TC DP vswing table

[Hsuan-Yu Lin (shanelin)]

https://lists.ubuntu.com/archives/kernel-team/2020-September/113335.html

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 5.8.0-19.20

---------------
linux (5.8.0-19.20) groovy; urgency=medium

  * groovy/linux: 5.8.0-19.20 -proposed tracker (LP: #1895120)

  * Please switch default, hwe, oem kernel flavours governor to
    CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y , such that advanced userspace
    utilities such as game-mode can be later used to rev-up to to performance,
    or rev-down to powersave. (LP: #1885730)
    - [Config] Set the default CPU governor to ONDEMAND

  * Packaging resync (LP: #1786013)
    - update dkms package versions
    - [Packaging] update variants

  * [WD19TB] external DP failed with DRM error message (LP: #1886165)
    - drm/i915/tgl+: Use the correct DP_TP_* register instances in MST encoders
    - drm/i915/tgl+: Fix TBT DPLL fractional divider for 38.4MHz ref clock

  * Groovy update: v5.8.8 upstream stable release (LP: #1895097)
    - hwmon: (pmbus/isl68137) remove READ_TEMPERATURE_1 telemetry for RAA228228
    - HID: quirks: Always poll three more Lenovo PixArt mice
    - drm/msm/dpu: Fix reservation failures in modeset
    - drm/msm/dpu: Fix scale params in plane validation
    - drm/msm/dpu: fix unitialized variable error
    - tty: serial: qcom_geni_serial: Drop __init from qcom_geni_console_setup
    - drm/msm: add shutdown support for display platform_driver
    - hwmon: (applesmc) check status earlier.
    - nvmet: Disable keep-alive timer when kato is cleared to 0h
    - drm/msm: enable vblank during atomic commits
    - habanalabs: unmap PCI bars upon iATU failure
    - habanalabs: validate packet id during CB parse
    - habanalabs: set clock gating according to mask
    - habanalabs: proper handling of alloc size in coresight
    - habanalabs: set max power according to card type
    - habanalabs: validate FW file size
    - habanalabs: check correct vmalloc return code
    - drm/msm/a6xx: fix gmu start on newer firmware
    - gfs2: add some much needed cleanup for log flushes that fail
    - hv_utils: return error if host timesysnc update is stale
    - hv_utils: drain the timesync packets on onchannelcallback
    - ceph: don't allow setlease on cephfs
    - i2c: iproc: Fix shifting 31 bits
    - drm/omap: fix incorrect lock state
    - irqchip/ingenic: Leave parent IRQ unmasked on suspend
    - cpuidle: Fixup IRQ state
    - nbd: restore default timeout when setting it to zero
    - s390: don't trace preemption in percpu macros
    - drm/amd/display: should check error using DC_OK
    - drm/amd/display: Reject overlay plane configurations in multi-display
      scenarios
    - drivers: gpu: amd: Initialize amdgpu_dm_backlight_caps object to 0 in
      amdgpu_dm_update_backlight_caps
    - drm/amd/display: Revert HDCP disable sequence change
    - drm/amd/display: Fix passive dongle mistaken as active dongle in EDID
      emulation
    - drm/amd/display: Keep current gain when ABM disable immediately
    - drm/amd/display: Retry AUX write when fail occurs
    - drm/amd/display: Fix memleak in amdgpu_dm_mode_config_init
    - xen/xenbus: Fix granting of vmalloc'd memory
    - fsldma: fix very broken 32-bit ppc ioread64 functionality
    - dmaengine: of-dma: Fix of_dma_router_xla...