Backport more recent driver for SKL, KBL and BXT graphics

[Timo Aaltonen]

We need to support Skylake (SKL), Kabylake (KBL) and Broxton (BXT) graphics in xenial, but the kernel driver is not fresh enough for proper support.

For the kernel the plan is to provide a separate driver module (i915_bpo) like for Skylake/Broadwell/Braswell in vivid. The drm/i915 driver in 4.4 is not recent enough for SKL/KBL/BXT, so pulling the driver from current drm-intel-next branch would provide what'll end up in 4.6. The i915 drivers will be modified so that only i915_bpo loads on SKL/KBL/BXT machines, and only there. The driver will get further updates along the way, and possibly also rebased to a later kernel release.

[Timo Aaltonen (tjaalton)]

Added initramfs-tools because i915_bpo needs to be added to the list of modules to include.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.4.0-9.24

---------------
linux (4.4.0-9.24) xenial; urgency=low

  [ Tim Gardner ]

  * Release Tracking Bug
    - LP: #1551319

  * AppArmor logs denial for when the device path is ENOENT (LP: #1482943)
    - SAUCE: apparmor: fix log of apparmor audit message when kern_path() fails

  * BUG: unable to handle kernel NULL pointer dereference (aa_label_merge) (LP:
    #1448912)
    - SAUCE: apparmor: Fix: insert race between label_update and label_merge
    - SAUCE: apparmor: Fix: ensure aa_get_newest will trip debugging if the
      replacedby is not setup
    - SAUCE: apparmor: Fix: label merge handling of marking unconfined and stale
    - SAUCE: apparmor: Fix: refcount race between locating in labelset and get
    - SAUCE: apparmor: Fix: ensure new labels resulting from merge have a
      replacedby
    - SAUCE: apparmor: Fix: label_vec_merge insertion
    - SAUCE: apparmor: Fix: deadlock in aa_put_label() call chain
    - SAUCE: apparmor: Fix: add required locking of __aa_update_replacedby on
      merge path
    - SAUCE: apparmor: Fix: convert replacedby update to be protected by the
      labelset lock
    - SAUCE: apparmor: Fix: update replacedby allocation to take a gfp parameter

  * apparmor kernel BUG kills firefox (LP: #1430546)
    - SAUCE: apparmor: Disallow update of cred when then subjective != the
      objective cred
    - SAUCE: apparmor: rework retrieval of the current label in the profile update
      case

  * sleep from invalid context in aa_move_mount (LP: #1539349)
    - SAUCE: apparmor: fix sleep from invalid context

  * s390x: correct restore of high gprs on signal return (LP: #1550468)
    - s390/compat: correct restore of high gprs on signal return

  * missing SMAP support (LP: #1550517)
    - x86/entry/compat: Add missing CLAC to entry_INT80_32

  * Floating-point exception handler receives empty Data-Exception Code in
    Floating Point Control register (LP: #1548414)
    - s390/fpu: signals vs. floating point control register

  * kvm fails to boot GNU Hurd kernels with 4.4 Xenial kernel (LP: #1550596)
    - KVM: x86: fix conversion of addresses to linear in 32-bit protected mode

  * Surelock GA2 SP1: capiredp01: cxl_init_adapter fails for CAPI devices
    0000:01:00.0 and 0005:01:00.0 after upgrading to 840.10 Platform firmware
    build fips840/b1208b_1604.840 (LP: #1532914)
    - cxl: Fix PSL timebase synchronization detection

  * [Feature]EDAC support for Knights Landing (LP: #1519631)
    - EDAC, sb_edac: Set fixed DIMM width on Xeon Knights Landing

  * Various failures of kernel_security suite on Xenial kernel on s390x arch
    (LP: #1531327)
    - [config] s390x -- CONFIG_DEFAULT_MMAP_MIN_ADDR=65536

  * Unable to install VirtualBox Guest Service in 15.04 (LP: #1434579)
    - [Config] Provides: virtualbox-guest-modules when appropriate

  * linux is missing provides for virtualbox-guest-modules [i386 amd64 x32] (LP:
    #1507588)
    - [Config] Provides: virtualbox-guest-modules when appropriate

  * Backport more recent driver for SKL, KBL and BXT graphics (LP: #1540390)
    - SAUCE: i915_bpo: Provide a backport driver for SKL, KBL & BXT graphics
    - SA...

[Timo Aaltonen (tjaalton)]

and SKL has been now tested on a certified system, things are still green:

https://certification.canonical.com/hardware/201507-18595/submission/109196/

[Thomas Bonfort (thomas-bonfort)]

I believe that this backport is causing screen flickering problems on Dell XPS13 9350, c.f. LP: #1554613 (where you'll find a bisect log pointing to this backport, and dmesg msg on first error)

[Timo Aaltonen (tjaalton)]

the backport will be soon updated to match what will be in 4.6-rc1, you can check if this mainline build is any better

http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-next/2016-03-01-wily/

(just install matching linux-image...deb)

[Thomas Bonfort (thomas-bonfort)]

4.5.0-997-generic #201603142201 from drm-intel-next still shows flickering

[Timo Aaltonen (tjaalton)]

ok, mind filing that upstream on bugs.freedesktop.org, product DRI, component DRM/Intel?

[Thomas Bonfort (thomas-bonfort)]

I've filed https://bugs.freedesktop.org/show_bug.cgi?id=94593 . After bisecting the intel-drm-next branch I believe 921ec285a6589cf3beb7f56a70744f75b09349f8 to be the culprit.

[Timo Aaltonen (tjaalton)]

cool, and now it would need a new bug here on launchpad :)