Black screen with Raspberry Pi 3 VC4 Mesa driver

Bug #1656164 reported by Alberto Aguirre
This bug affects 2 people
Affects Status Importance Assigned to Milestone
Fix Released
Alberto Aguirre
mir (Ubuntu)
Fix Released

Bug Description

Using mir 0.25 on a rpi3 using the vc4 mesa driver, a blank screen is seen when starting mir_demo_server for example.

Mir 0.24.1 works fine.

Tags: black-screen

Related branches

Revision history for this message
Alberto Aguirre (albaguirre) wrote :

Looks like drmModeCrtcGetGamma returns zero filled gamma tables, which are later set with drmModeCrtcSetGamma even though the tables are not modified.

summary: - blank screen with rpi3/vc4 mesa driver
+ Black screen with Raspberry Pi 3 VC4 Mesa driver
Changed in mir:
importance: Undecided → High
status: New → Triaged
tags: added: black-screen
Revision history for this message
Alberto Aguirre (albaguirre) wrote :

Ok after looking at drm implementation, this doesn't seem like a driver bug.

DRM's design is such that drmModeCrtcGetGamma only returns what has been previously set by drmModeCrtcSetGamma.

In fact, on the kernel side, there's no function pointer defined to query the h/w/ for the gamma tables in the crtc structure - drm's drmModeCrtcGetGamma ioctl handler just returns whatever has been previously set by drmModeCrtcSetGamma (which explains the zeros).

The reason this issue may have gone unnoticed on an Ubuntu classic system is that X11 probably had already called drmModeCrtcSetGamma by the time mir ran so a good lut was already in place.

Changed in mir:
assignee: nobody → Alberto Aguirre (albaguirre)
milestone: none → 0.26.0
Changed in mir:
milestone: 0.26.0 → 1.0.0
Changed in mir:
status: Triaged → In Progress
Revision history for this message
Mir CI Bot (mir-ci-bot) wrote :

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 1.0.0

Changed in mir:
status: In Progress → Fix Committed
Changed in mir:
milestone: 1.0.0 → 0.26.0
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (7.2 KiB)

This bug was fixed in the package mir - 0.26.0+17.04.20170126.3-0ubuntu1

mir (0.26.0+17.04.20170126.3-0ubuntu1) zesty; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 0.26.0 (https://launchpad.net/mir/+milestone/0.26.0)
    - ABI summary:
      . mirclient ABI unchanged at 9
      . mirserver ABI bumped to 43
      . mircommon ABI unchanged at 7
      . mirplatform ABI unchanged at 14
      . mirprotobuf ABI unchanged at 3
      . mirplatformgraphics ABI unchanged at 11
      . mirclientplatform ABI unchanged at 5
      . mirinputplatform ABI unchanged at 6
      . mircore ABI unchanged at 1
    - Enhancements:
      . New/improved toolkit APIs: MirInputConfig and related functions,
        MirWindow and related functions, DisplayConfig and related functions,
        MirScreencastSpec and related functions,
      . Support for configuring input configuration
      . Introduce toolkit extension mechanism for platform specific APIs.
      . Toolkit extensions for: mesa_drm_auth, set_gbm_device and
      . Screencasting to a specific MirBuffer.
      . Add DisplayConfigurationController::base_configuration() so downstreams
        can get the base configuration. (Weirdly they can already set it.).
      . x11 platform: allow adjustable scale parameter.
      . Added EDID support: client API, server logging and in mirout.
      . mirout: Add newer attributes only available in the new display
        config API: scaling factor, subpixel arrangement and form factor.
      . mirout: Log the orientation and logical size of each output too.
      . Replace the mir::Server-overridable Reports with Observers.
      . Add xkbcommon to mirclient.pc Requires.private.
      . Deprecate legacy toolkit APIs that will be removed in Mir 1.0
      . Introduced 'client-side vsync', which dramatically reduces latency
        from the client to the screen (particularly for nested servers like
    - Bugs fixed:
      . [performance] Restore support for better-than-triple buffering by
        default. (LP: #1240909)
      . Frame rate is artificially low on Diamondville Intel Atom systems due
        to aggressive power management (LP: #1388490)
      . [testsfail] failure in CI in
        (LP: #1394369)
      . [trusted prompt sessions] Can't open two prompt sessions at the same
        time (LP: #1494197)
      . Changing scale, formFactor or DPI in display configuration causes
        renderer teardown/recreate unnecessarily (LP: #1556142)
      . [testsfail] ApplicationNotRespondingDetection.failure_to_pong_is_
        noticed (LP: #1570327)
      . CI failure in TestClientInput.receives_one_touch_event_per_frame
        (LP: #1570698)
      . Mir-on-X mouse input is jerky/stuttery compared to Mir-on-KMS
        (LP: #1576600)
      . [regression] Two fingers in mir_proving_server now resizes/moves app
        windows (two finger apps unusable) (LP: #1586311)
      . Pointer/cursor input lag in unity8 session (LP: #1591328)
      . PointerConfinement.test_we_update_our_confined_region_on_a_resize


Changed in mir (Ubuntu):
status: New → Fix Released
Changed in mir:
status: Fix Committed → Fix Released
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