| Message ID | 1442881308-24940-1-git-send-email-matthew.d.roper@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 64fc5ca..2149ac7 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -352,6 +352,8 @@ retry: drm_for_each_plane(plane, dev) { struct drm_plane_state *plane_state; + plane->old_fb = plane->fb; + plane_state = drm_atomic_get_plane_state(state, plane); if (IS_ERR(plane_state)) { ret = PTR_ERR(plane_state); @@ -385,6 +387,14 @@ retry: if (ret != 0) goto fail; + drm_for_each_plane(plane, dev) { + if (plane->fb) + drm_framebuffer_reference(plane->fb); + if (plane->old_fb) + drm_framebuffer_unreference(plane->old_fb); + plane->old_fb = NULL; + } + return 0; fail:
Starting with commit commit 28cc504e8d52248962f5b485bdc65f539e3fe21d Author: Rob Clark <robdclark@gmail.com> Date: Tue Aug 25 15:36:00 2015 -0400 drm/i915: enable atomic fb-helper I've been seeing some panics on i915 when the DRM master shuts down that appear to be caused by using an already-freed framebuffer (i.e., we're unexpectedly dropping our initial FB's reference count to 0 and freeing it, which causes a crash when we try to restore it later). Digging deeper, the state FB refcounting is working as expected, but we seem to be missing proper refcounting on the legacy plane->fb pointers in the new atomic fbdev code. Tracking plane->old_fb and then doing a ref/unref at the end of the fbdev restore like we do in the legacy ioctl's ensures we don't miscount references on plane->fb and avoids the panics. Cc: Rob Clark <robdclark@gmail.com> Cc: intel-gfx@lists.freedesktop.org Signed-off-by: Matt Roper <matthew.d.roper@intel.com> --- I don't see any existing bugzilla's (or mailing list complaints) for this, which surprises me a bit since it seems to be very easy to reproduce for me on latest drm-intel-nightly running on IVB...boot the system, load X, kill X, panic. drivers/gpu/drm/drm_fb_helper.c | 10 ++++++++++ 1 file changed, 10 insertions(+)