kernel-packages team mailing list archive

[Timo Aaltonen <tjaalton@xxxxxxxxxx>]

Public bug reported:

Display power well can cause issues like blank screen when logging in
after resume from suspend, so it's best to disable it for now like
upstream did in v4.4-rc1:

commit 1b0e3a049efe471c399674fd954500ce97438d30
Author: Imre Deak <imre.deak@xxxxxxxxx>
Date:   Thu Nov 5 23:04:11 2015 +0200

    drm/i915/skl: disable display side power well support for now
    
    The display power well support on this platform is in a somewhat broken
    state atm, so disable it by default.
    
    This in effect will get rid of incorrect assert WARNs about the CSR/DMC
    firmware not being loaded during power well toggling. It also removes a
    problem during driver loading where a register is accessed while its
    backing power well is down, resulting in another WARN. Until we come up
    with the root cause of the second problem and the proper fix for both
    issues, keep all display side power wells on.
    
    Also clarify a bit the option description.
    
    Reported-by: Dave Airlie <airlied@xxxxxxxxxx>
    Reference: http://mid.gmane.org/CAPM=9tyjBQjSBTKa49cRr6SYkpNW7Pq-fUFznZZ8Y1snvvk7mA@xxxxxxxxxxxxxx
    Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
    Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
    Link: http://patchwork.freedesktop.org/patch/msgid/1446757451-2777-1-git-send-email-imre.deak@xxxxxxxxx
    Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>

** Affects: linux (Ubuntu)
     Importance: Undecided
     Assignee: Timo Aaltonen (tjaalton)
         Status: Triaged

** Affects: linux (Ubuntu Vivid)
     Importance: Undecided
         Status: Triaged

** Affects: linux (Ubuntu Wily)
     Importance: Undecided
         Status: Triaged

** Also affects: linux (Ubuntu Wily)
   Importance: Undecided
       Status: New

** Also affects: linux (Ubuntu Vivid)
   Importance: Undecided
       Status: New

** Changed in: linux (Ubuntu)
       Status: New => Triaged

** Changed in: linux (Ubuntu)
     Assignee: (unassigned) => Timo Aaltonen (tjaalton)

** Changed in: linux (Ubuntu Vivid)
       Status: New => Triaged

** Changed in: linux (Ubuntu Wily)
       Status: New => Triaged

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https://bugs.launchpad.net/bugs/1526220

Title:
  [SKL] Disable display power well

Status in linux package in Ubuntu:
  Triaged
Status in linux source package in Vivid:
  Triaged
Status in linux source package in Wily:
  Triaged

Bug description:
  Display power well can cause issues like blank screen when logging in
  after resume from suspend, so it's best to disable it for now like
  upstream did in v4.4-rc1:

  commit 1b0e3a049efe471c399674fd954500ce97438d30
  Author: Imre Deak <imre.deak@xxxxxxxxx>
  Date:   Thu Nov 5 23:04:11 2015 +0200

      drm/i915/skl: disable display side power well support for now
      
      The display power well support on this platform is in a somewhat broken
      state atm, so disable it by default.
      
      This in effect will get rid of incorrect assert WARNs about the CSR/DMC
      firmware not being loaded during power well toggling. It also removes a
      problem during driver loading where a register is accessed while its
      backing power well is down, resulting in another WARN. Until we come up
      with the root cause of the second problem and the proper fix for both
      issues, keep all display side power wells on.
      
      Also clarify a bit the option description.
      
      Reported-by: Dave Airlie <airlied@xxxxxxxxxx>
      Reference: http://mid.gmane.org/CAPM=9tyjBQjSBTKa49cRr6SYkpNW7Pq-fUFznZZ8Y1snvvk7mA@xxxxxxxxxxxxxx
      Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
      Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
      Link: http://patchwork.freedesktop.org/patch/msgid/1446757451-2777-1-git-send-email-imre.deak@xxxxxxxxx
      Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>

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