[Intel-gfx] [PATCH 2/2] drm/fb-helper: Fix fb refcounting in pan_display_atomic

[Rodrigo Vivi]

Thanks!

Tested-by: Rodrigo Vivi <rodrigo.vivi at intel.com>


On Fri, Oct 16, 2015 at 9:35 AM Rob Clark <robdclark at gmail.com> wrote:

> On Fri, Oct 16, 2015 at 12:23 PM, Daniel Vetter <daniel.vetter at ffwll.ch>
> wrote:
> > In
> >
> > commit bbb1e52402b2a288b09ae37e8182599931c7e9df
> > Author: Rob Clark <robdclark at gmail.com>
> > Date:   Tue Aug 25 15:35:58 2015 -0400
> >
> >     drm/fb-helper: atomic restore_fbdev_mode()..
> >
> > we've forgotten to do the plane->old_fb refcount dance for
> > pan_display_atomic, which can result in refcount leaks if the current
> > configuration is not from fbcon. Which apparently can happen when
> > vt-switching - fbcon does a pan first before a set_par.
>
> oh, whoops
>
> > OCD-align function parameters while at it.
>
> did you mean to drop that line from the commit msg, or include an
> extra hunk that you missed?
>
> at any rate,
>
> Reviewed-by: Rob Clark <robdclark at gmail.com>
>
> > Cc: Rob Clark <robdclark at gmail.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi at gmail.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92483
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > ---
> >  drivers/gpu/drm/drm_fb_helper.c | 27 +++++++++++++++++++++++++--
> >  1 file changed, 25 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_fb_helper.c
> b/drivers/gpu/drm/drm_fb_helper.c
> > index 0ac0fcc9b0d2..b2cf28dd90fe 100644
> > --- a/drivers/gpu/drm/drm_fb_helper.c
> > +++ b/drivers/gpu/drm/drm_fb_helper.c
> > @@ -1249,6 +1249,8 @@ retry:
> >
> >                 mode_set = &fb_helper->crtc_info[i].mode_set;
> >
> > +               mode_set->crtc->primary->old_fb =
> mode_set->crtc->primary->fb;
> > +
> >                 mode_set->x = var->xoffset;
> >                 mode_set->y = var->yoffset;
> >
> > @@ -1264,13 +1266,34 @@ retry:
> >         info->var.xoffset = var->xoffset;
> >         info->var.yoffset = var->yoffset;
> >
> > -       return 0;
> >
> >  fail:
> > +       for(i = 0; i < fb_helper->crtc_count; i++) {
> > +               struct drm_mode_set *mode_set;
> > +               struct drm_plane *plane;
> > +
> > +               mode_set = &fb_helper->crtc_info[i].mode_set;
> > +               plane = mode_set->crtc->primary;
> > +
> > +               if (ret == 0) {
> > +                       struct drm_framebuffer *new_fb =
> plane->state->fb;
> > +
> > +                       if (new_fb)
> > +                               drm_framebuffer_reference(new_fb);
> > +                       plane->fb = new_fb;
> > +                       plane->crtc = plane->state->crtc;
> > +
> > +                       if (plane->old_fb)
> > +
>  drm_framebuffer_unreference(plane->old_fb);
> > +               }
> > +               plane->old_fb = NULL;
> > +       }
> > +
> >         if (ret == -EDEADLK)
> >                 goto backoff;
> >
> > -       drm_atomic_state_free(state);
> > +       if (ret != 0)
> > +               drm_atomic_state_free(state);
> >
> >         return ret;
> >
> > --
> > 2.5.1
> >
>
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