On Mon, Mar 02, 2015 at 04:35:20PM +0100, Daniel Vetter wrote:
> This reverts commit 3f678c96abb43a977d2ea41aefccdc49e8a3e896.
>
> We've been a bit too optimistic with this one here :(
>
> The trouble is that internally we're still using these plane
> update/disable hooks. Which was totally ok pre-atomic since the drm
> core did all the book-keeping updating and these just mostly updated
> hw state. But with atomic there's lots more going on, and it causes
> heaps of trouble with the load detect code.
>
> This one specifically cause a deadlock since both the load detect code
> and the nested plane atomic helper functions tried to grab the same
> locks. It only blows up because of the evil tricks though we play with
> the implicit ww acquire context.
>
> Applying this revert unearths the NULL deref on already freed
> framebuffer objects reported as a regression in 4.0 by various people.
>
> Fixing this will be fairly invasive, hence revert even for the
> 4.1-next queue.
>
> Cc: Matt Roper
> Cc: Linus Torvalds
> Cc: Paul Bolle
> Signed-off-by: Daniel Vetter
Queued for -next with Matt's ack.
-Daniel
> ---
> Just to make it really clear: This is 4.1-next material. It's simply
> the explanation for why we didn't notice the oops ourselves. The 4.0
> oops itself looks like some glue lacking in the load detect code,
> still working on that one.
> -Daniel
> ---
> drivers/gpu/drm/i915/intel_display.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index 3156d77b2215..cc3305e30c1b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12179,8 +12179,8 @@ void intel_plane_destroy(struct drm_plane *plane)
> }
>
> const struct drm_plane_funcs intel_plane_funcs = {
> - .update_plane = drm_atomic_helper_update_plane,
> - .disable_plane = drm_atomic_helper_disable_plane,
> + .update_plane = drm_plane_helper_update,
> + .disable_plane = drm_plane_helper_disable,
> .destroy = intel_plane_destroy,
> .set_property = drm_atomic_helper_plane_set_property,
> .atomic_get_property = intel_plane_atomic_get_property,
> --
> 1.8.4.rc3
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
