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  1. 09 Mar, 2015 1 commit
  3. 04 Mar, 2015 1 commit
  5. 03 Mar, 2015 1 commit
    • Daniel Vetter's avatar
      drm/i915: Fix modeset state confusion in the load detect code · 9128b040
      Daniel Vetter authored 
      This is a tricky story of the new atomic state handling and the legacy
code fighting over each another. The bug at hand is an underrun of the
framebuffer reference with subsequent hilarity caused by the load
detect code. Which is peculiar since the the exact same code works
fine as the implementation of the legacy setcrtc ioctl.

Let's look at the ingredients:

- Currently our code is a crazy mix of legacy modeset interfaces to
  set the parameters and half-baked atomic state tracking underneath.
  While this transition is going we're using the transitional plane
  helpers to update the atomic side (drm_plane_helper_disable/update
  and friends), i.e. plane->state->fb. Since the state structure owns
  the fb those functions take care of that themselves.

  The legacy state (specifically crtc->primary->fb) is still managed
  by the old code (and mostly by the drm core), with the fb reference
  counting done by callers (core drm for the ioctl or the i915 load
  detect code). The relevant commit is

  commit ea2c67bb
  Author: Matt Roper <matthew.d.roper@intel.com>
  Date:   Tue Dec 23 10:41:52 2014 -0800

      drm/i915: Move to atomic plane helpers (v9)

- drm_plane_helper_disable has special code to handle multiple calls
  in a row - it checks plane->crtc == NULL and bails out. This is to
  match the proper atomic implementation which needs the crtc to get
  at the implied locking context atomic updates always need. See

  commit acf24a39
  Author: Daniel Vetter <daniel.vetter@ffwll.ch>
  Date:   Tue Jul 29 15:33:05 2014 +0200

      drm/plane-helper: transitional atomic plane helpers

- The universal plane code split out the implicit primary plane from
  the CRTC into it's own full-blown drm_plane object. As part of that
  the setcrtc ioctl (which updated both the crtc mode and primary
  plane) learned to set crtc->primary->crtc on modeset to make sure
  the plane->crtc assignments statate up to date in

  commit e13161af
  Author: Matt Roper <matthew.d.roper@intel.com>
  Date:   Tue Apr 1 15:22:38 2014 -0700

      drm: Add drm_crtc_init_with_planes() (v2)

  Unfortunately we've forgotten to update the load detect code. Which
  wasn't a problem since the load detect modeset is temporary and
  always undone before we drop the locks.

- Finally there is a organically grown history (i.e. don't ask) around
  who sets the legacy plane->fb for the various driver entry points.
  Originally updating that was the drivers duty, but for almost all
  places we've moved that (plus updating the refcounts) into the core.
  Again the exception is the load detect code.

Taking all together the following happens:
- The load detect code doesn't set crtc->primary->crtc. This is only
  really an issue on crtcs never before used or when userspace
  explicitly disabled the primary plane.

- The plane helper glue code short-circuits because of that and leaves
  a non-NULL fb behind in plane->state->fb and plane->fb. The state
  fb isn't a real problem (it's properly refcounted on its own), it's
  just the canary.

- Load detect code drops the reference for that fb, but doesn't set
  plane->fb = NULL. This is ok since it's still living in that old
  world where drivers had to clear the pointer but the core/callers
  handled the refcounting.

- On the next modeset the drm core notices plane->fb and takes care of
  refcounting it properly by doing another unref. This drops the
  refcount to zero, leaving state->plane now pointing at freed memory.

- intel_plane_duplicate_state still assume it owns a reference to that
  very state->fb and bad things start to happen.

Fix this all by applying the same duct-tape as for the legacy setcrtc
ioctl code and set crtc->primary->crtc properly.

Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reported-and-tested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: default avatarPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9128b040
  7. 27 Feb, 2015 7 commits
  9. 26 Feb, 2015 1 commit
  11. 25 Feb, 2015 3 commits
    • Matt Roper's avatar
      drm/i915: Ensure crtc_state backpointer is always initialized · 07878248
      Matt Roper authored 
      As we transition to full atomic modesetting, we want to be able to pass
intel_crtc_state around in various places that we pass intel_crtc
directly today.  Ensure that the ->crtc backpointer is properly
initialized in case we need to get back to the associated CRTC.
Signed-off-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      07878248
    • Matt Roper's avatar
      drm/i915: Use enabled value from crtc_state rather than crtc (v2) · 83d65738
      Matt Roper authored 
      As vendors transition their drivers from legacy to atomic there's some
duplication of data between drm_crtc and drm_crtc_state (since
unconverted drivers likely won't have a state structure).

i915 is partially converted and does have a crtc->state structure, but
still uses direct crtc fields internally in many places, which causes
the two sets of data to get out of sync.  As of commit

        commit 31c946e8
        Author: Daniel Vetter <daniel.vetter@ffwll.ch>
        Date:   Sun Feb 22 12:24:17 2015 +0100

            drm: If available use atomic state in getcrtc ioctl

            This way drivers fully converted to atomic don't need to update these
            legacy state variables in their modeset code any more.
Reviewed-by: default avatarRob Clark <robdclark@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>

the DRM core starts assuming that the presence of a ->state structure
implies that it should make use of the values stored there which, on
i915, leads to the core code using stale values for CRTC 'enabled'
status.

Let's switch over to using the state value of 'enable' internally rather
than using the drm_crtc field.  This ensures that our driver internals
are working from the same data that the DRM core is, avoiding
mismatches.

This patch was generated with Coccinelle using the following semantic
patch:

        <smpl>
        @@
        struct drm_crtc C;
        struct drm_crtc *CP;
        @@
        (
        - C.enabled
        + C.state->enable
        |
        - CP->enabled
        + CP->state->enable
        )

        // For assignments, we still update the legacy value as well as the state value
        // so add an extra assignment statement for that.
        @@
        struct drm_crtc C;
        struct drm_crtc *CP;
        expression E;
        @@
        (
          C.state->enable = E;
        + C.enabled = E;
        |
          CP->state->enable = E;
        + CP->enabled = E;
        )
        </smpl>

The crtc->mode and crtc->hwmode fields should probably be transitioned
over as well eventually, but we seem to do an okay job of keeping those
up-to-date already so I want to minimize the changes that will clash
with Ander's in-progress atomic work.

v2: Don't remove the assignments to the legacy value when we assign to
    the state value.  A second cocci stanza takes care of adding the
    legacy assignment back where appropriate.  (Daniel)

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Signed-off-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      83d65738
    • Rodrigo Vivi's avatar
      drm/i915: Fix frontbuffer false positve. · 62e537f8
      Rodrigo Vivi authored 
      This return 0 without setting atomic bits on fb == crtc->cursor->fb
where causing frontbuffer false positives.

According to Daniel:

The original regression seems to have been introduced in the original
check/commit split:

commit 757f9a3e
Author: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Date:   Wed Sep 24 14:20:24 2014 -0300

    drm/i915: move check of intel_crtc_cursor_set_obj() out

Which already cause other trouble, resulting in the check getting moved in

commit e391ea88
Author: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Date:   Wed Sep 24 14:20:25 2014 -0300

    drm/i915: Fix not checking cursor and object sizes

The frontbuffer tracking itself only was broken when we shifted it into
the check/commit logic with:

commit 32b7eeec
Author: Matt Roper <matthew.d.roper@intel.com>
Date:   Wed Dec 24 07:59:06 2014 -0800

    drm/i915: Refactor work that can sleep out of commit (v7)

v2: When putting more debug prints I notice the solution was simpler
than I thought. AMS design is solid, just this return was wrong.
Sorry for the noise.

v3: Remove the entire chunck that would probably
    be removed by gcc anyway. (by Daniel)

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      62e537f8
  13. 24 Feb, 2015 3 commits
  15. 23 Feb, 2015 5 commits
  17. 13 Feb, 2015 18 commits
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