On Friday 11 April 2014 12:10 PM, Tomi Valkeinen wrote:
<snip>
Does drm_framebuffer_remove get called when we abort the application, or
unload omapdrm, or both?
Both. When we abort an app, drm_framebuffer_remove gets called for the
fb that the app created. When we unload omapdrm, it gets called for the
main fb, used for fb console.
- fb->refcount.refcount > 1, so it goes to disable stuff
- drm_plane_force_disable is called for the primary plane
Maybe we need to make sure that this func is called only when our driver
has unreferenced it. In that case, we would probably need to flush our
queue and disable interrupts(so that we don't queue more work).
Hmm, sorry, call which func, unreferenced what? =)
Do you mean we should call drm_framebuffer_remove() only if
fb->refcount.refcount == 1. That should be possible, and would probably
remove the issue, but it would just be going around the actual problem.
Yes, I meant our driver should call drm_framebuffer_remove() only when
we are know that the fb reference omapdrm had taken(the one in
update_pin), has a corresponding fb unref called(in unpin_worker).
Isn't that something omapdrm should take care of?
<snip>
I can't get the corresponding reference for it either. But I can count 3
of them when you run fbcon with drm's fb helper.
- One ref is taken in the drm_framebuffer_init called from
omap_fbdev_create.
- fbcon will call fb_set_par, which calls drm_fb_helper_set_par, that
seems to take a refernce to the fb in the end.
This one is not called for a normal app, as there's no fbdev framebuffer
for it. Note that the funcs I mention deal with drm framebuffer, which
is not the fbdev framebuffer (confusing =). fbdev fb is only used for
the "root" framebuffer. And, of course, fbdev fb uses the drm fb
Yes. In the case of a normal app, we would call the ADD_FB2 ioctl to get
a drm_framebuffer, that will internally take a fb reference. So the
count won't seem to go beyond 2.
functionality.
- drm_crtc_helper_set_config() calls the omadrm specific mode_set
drm_crtc_funcs, which eventually calls a drm_framebuffer_reference in
update_pin().
Yep.
I forgot to mention that if I comment out the unref in
drm_plane_force_disable(), the ref counts match and all looks fine. And
also that I didn't see this issue with 3.14.
That's strange. I guess there must be an extra unref happening somewhere
in the newer commits. Did you try a diff of drm code between the 2
kernels? :)
Archit
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