[SKL, i915_bpo] System hang when switching between extended/mirror modes

[Timo Aaltonen]

Switching between extended/mirror modes when an external monitor is plugged in causes a system hang on at least some machines, like my SKL-Y ultramobile test system. It needs a backport of an upstream commit from 4.3, modified to work on 4.2-based i915_bpo:

commit f015c5518879fb3e578caaa63806617468a24045
Author: Ville Syrjälä <email address hidden>
Date: Wed Jun 24 22:00:02 2015 +0300

    drm/i915: Split atomic wm update to pre and post variants
--

the watermark stuff is Skylake-specific, so can't regress BSW/BDW. This has been tested on a number of SKL machines now, fixing the bug.

[Chih-Hsyuan Ho (chih)]

Verified the kernel build with the said patch on multiple failed Intel SKL systems and it made display mode switching work reliably.

[Leon Liao (lihow731)]

On PAR4-DVT2-C2U with the kernel 3.19.0-28.30+bpo1 (download from http://koti.kapsi.fi/~tjaalton/skl/), the system hung doest not occurs when switching VGA output.

[Brad Figg (brad-figg)]

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-vivid' to 'verification-done-vivid'.

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!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.2.0-10.11

---------------
linux (4.2.0-10.11) wily; urgency=low

  [ Andy Whitcroft ]

  * Release Tracking Bug
    - LP: #1495208
  * No change rebuild to avoid issues with leading zero bytes on
    internal module signing key. (see launchpad bug 1494943)

  [ Ming Lei ]

  * [Config] SERIAL_8250_DW=y for arm64

  [ Upstream Kernel Changes ]

  * drm/i915: Move WaBarrierPerformanceFixDisable:skl to skl code from chv
    code
    - LP: #1484486
  * drm/i915/gen8: Add infrastructure to initialize WA batch buffers
    - LP: #1484486
  * drm/i915/gen8: Re-order init pipe_control in lrc mode
    - LP: #1484486
  * drm/i915/gen8: Add WaDisableCtxRestoreArbitration workaround
    - LP: #1484486
  * drm/i915/gen8: Add WaFlushCoherentL3CacheLinesAtContextSwitch
    workaround
    - LP: #1484486
  * drm/i915: Bail out early if WA batch is not available for given Gen
    - LP: #1484486
  * drm/i915/gen8: Add WaClearSlmSpaceAtContextSwitch workaround
    - LP: #1484486
  * drm/i915: Update WaFlushCoherentL3CacheLinesAtContextSwitch
    - LP: #1484486
  * drm/i915/gen9: Implement WaDisableKillLogic for gen 9
    - LP: #1484486
  * drm/i915: Enable WA batch buffers for Gen9
    - LP: #1484486
  * drm/i915/gen9: Add WaDisableCtxRestoreArbitration workaround
    - LP: #1484486
  * drm/i915: Update wa_ctx_emit() macro as per kernel coding guidelines
    - LP: #1484486
  * drm/i915/gen9: Add WaFlushCoherentL3CacheLinesAtContextSwitch
    workaround
    - LP: #1484486
  * drm/i915/gen9: Add
    WaSetDisablePixMaskCammingAndRhwoInCommonSliceChicken
    - LP: #1484486
  * drm/i915:skl: Add WaEnableGapsTsvCreditFix
    - LP: #1484486
  * drm/i915/skl: revert duplicated WaBarrierPerformanceFixDisable:skl
    - LP: #1484486
  * drm/i915/skl: Don't expose the top most plane on gen9 display
    - LP: #1484486
  * drm/i915/skl WaDisableSbeCacheDispatchPortSharing
    - LP: #1484486
  * drm/i915/skl: WaIgnoreDDIAStrap is forever, always init DDI A
    - LP: #1484486
  * drm/i915: reduce indent in i9xx_hpd_irq_handler
    - LP: #1484531
  * drm/i915: reduce duplicate conditions in i9xx_hpd_irq_handler
    - LP: #1484531
  * drm/i915: reduce indent in intel_hpd_irq_handler
    - LP: #1484531
  * drm/i915: group all hotplug related fields into a new struct in
    dev_priv
    - LP: #1484531
  * drm/i915: add for_each_hpd_pin to iterate over hotplug pins
    - LP: #1484531
  * drm/i915: simplify conditions for skipping the 2nd hpd loop iterations
    - LP: #1484531
  * drm/i915: put back the indent in intel_hpd_irq_handler
    - LP: #1484531
  * drm/i915: merge the two hpd loops in intel_hpd_irq_handler to one
    - LP: #1484531
  * drm/i915: simplify condition for digital port
    - LP: #1484531
  * drm/i915: abstract away platform specific parts from hpd handling
    - LP: #1484531
  * drm/i915: Handle HPD when it has actually occurred
    - LP: #1484531
  * drm/i915: Set power domain for DDI-E
    - LP: #1484531
  * drm/i915: Set alternate aux for DDI-E
    - LP: #1484531
  * drm/i915/skl: enable DDI-E hotplug
    - LP: #1484531
  * drm/i915/bxt: fix DDI PHY vswing scale value setting
    - LP: #1494163
  * drm/i915/skl: Buf...

[Timo Aaltonen (tjaalton)]

works fine with the new vivid kernel

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.19.0-30.33

---------------
linux (3.19.0-30.33) vivid; urgency=low

  [ Brad Figg ]

  * Release Tracking Bug
    - LP: #1498065
  * Revert "[Config]
    MFD_INTEL_LPSS/MFD_INTEL_LPSS_ACPI/MFD_INTEL_LPSS_PCI=m"
    - LP: #1498137
  * [Config] Disable the MFD_INTEL_LPSS* driver

linux (3.19.0-30.32) vivid; urgency=low

  [ Brad Figg ]

  * Release Tracking Bug
    - LP: #1498065

  [ Upstream Kernel Changes ]

  * net: Fix skb_set_peeked use-after-free bug
    - LP: #1497184

linux (3.19.0-29.31) vivid; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1493902

  [ Ander Conselvan de Oliveira ]

  * SAUCE: i915_bpo: Set ddi_pll_sel in DP MST path
    - LP: #1483320

  [ Chris J Arges ]

  * [Config] DEFAULT_IOSCHED="deadline" for ppc64el
    - LP: #1469829

  [ Chris Wilson ]

  * SAUCE: i915_bpo: drm/i915: Flag the execlists context object as dirty
    after every use
    - LP: #1489501

  [ Daniel Vetter ]

  * SAUCE: i915_bpo: drm/i915: Only dither on 6bpc panels
    - LP: #1489501

  [ David Henningsson ]

  * SAUCE: drm/i915: Add audio pin sense / ELD callback
    - LP: #1490895
  * SAUCE: drm/i915: Call audio pin/ELD notify function
    - LP: #1490895
  * SAUCE: ubuntu/i915: Call audio pin/ELD notify function
    - LP: #1490895
  * SAUCE: ALSA: hda - Add "hdac_acomp" global variable
    - LP: #1490895
  * SAUCE: ALSA: hda - allow codecs to access the i915 pin/ELD callback
    - LP: #1490895
  * SAUCE: ALSA: hda - Wake the codec up on pin/ELD notify events
    - LP: #1490895

  [ Jani Nikula ]

  * SAUCE: i915_bpo: Revert "drm/i915: Allow parsing of variable size child
    device entries from VBT"
    - LP: #1489501

  [ Maarten Lankhorst ]

  * SAUCE: i915_bpo: drm/i915: calculate primary visibility changes instead
    of calling from set_config
    - LP: #1489501
  * SAUCE: i915_bpo: drm/i915: Commit planes on each crtc separately.
    - LP: #1489501

  [ Thulasimani,Sivakumar ]

  * SAUCE: i915_bpo: Revert "drm/i915: Add eDP intermediate frequencies for
    CHV"
    - LP: #1489501
  * SAUCE: i915_bpo: drm/i915: remove HBR2 from chv supported list
    - LP: #1489501
  * SAUCE: i915_bpo: drm/i915: Avoid TP3 on CHV
    - LP: #1489501

  [ Timo Aaltonen ]

  * Revert "SAUCE: i915_bpo: drm/i915: Allow parsing of variable size child
    device entries from VBT, addendum v2"
    - LP: #1489501
  * SAUCE: Migrate Broadwell to i915_bpo.
    - LP: #1483320

  [ Upstream Kernel Changes ]

  * tcp: fix recv with flags MSG_WAITALL | MSG_PEEK
    - LP: #1486146
  * powerpc/powernv: Fix the overflow of OPAL message notifiers head array
    - LP: #1487085
  * xhci: call BIOS workaround to enable runtime suspend on Intel Braswell
    - LP: #1489292
  * PM / QoS: Make it possible to expose device latency tolerance to
    userspace
    - LP: #1488395
  * ACPI / PM: Attach ACPI power domain only once
    - LP: #1488395
  * Driver core: wakeup the parent device before trying probe
    - LP: #1488395
  * klist: implement klist_prev()
    - LP: #1488395
  * driver core: implement device_for_each_child_reverse()
    - LP: #1488395
  * mfd: make mfd_remove_devices() iterate in reverse order
    ...