[PATCH 03/27] drm/arc: Actually bother with handling atomic events.

[Daniel Vetter]

On Fri, Jun 10, 2016 at 03:01:03PM +0000, Alexey Brodkin wrote:
> Hi Daniel,
> 
> On Fri, 2016-06-10 at 16:54 +0200, Daniel Vetter wrote:
> > On Fri, Jun 10, 2016 at 04:19:27PM +0200, Daniel Vetter wrote:
> > > 
> > > On Fri, Jun 10, 2016 at 01:23:22PM +0000, Alexey Brodkin wrote:
> > > > 
> > > > Hi Daniel,
> > > > 
> > > > On Thu, 2016-06-09 at 16:37 +0200, Daniel Vetter wrote:
> > > > > 
> > > > > On Thu, Jun 9, 2016 at 4:31 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> > > > > > 
> > > > > > 
> > > > > > On Thu, Jun 9, 2016 at 4:29 PM, Alexey Brodkin
> > > > > > <Alexey.Brodkin at synopsys.com> wrote:
> > > > > > > 
> > > > > > > 
> > > > > > > Hi Daniel,
> > > > > > > 
> > > > > > > On Thu, 2016-06-09 at 15:52 +0200, Daniel Vetter wrote:
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > The fake implementation is fundamentally racy, and I don't want to write
> > > > > > > > helpers which can't be used correctly. Anyway I think without this patch
> > > > > > > > (or something similar) arcpgu will stall badly with the new nonblocking
> > > > > > > > helpers, because arcpgu didn't bother at all to implement nonblocking. Can
> > > > > > > > you pls ack this, or even better, test the entire patch series? The
> > > > > > > > helpers themselves should work, but in all 5 drivers tested thus far they
> > > > > > > > discovered some bugs.
> > > > > > > Sure I will happily test this series.
> > > > > > > The only question then is what should I use as a proper base?
> > > > > > It should apply on drm-next from Dave.
> > > > > And indeed it won't work at all because arcpgu doesn't call
> > > > > drm_crtc_handle_vblank anywhere. So you need to add your patch to
> > > > > enable vblank interrupts somewhere. Note that as long as you leave
> > > > > max_vblank_counter as 0, the only bits you need is drm_vblank_init and
> > > > > drm_crtc_handle_vblanke() from the irq handler.
> > > > So is there any sense in testing that series if vblank interrupt is not yet
> > > > supported (I'm looking forward to implementing it sometime soon but definitely
> > > > I'm not there yet)?
> > > Well, it might break your driver, so yes. I'm ofc happy to help unbreak it,
> > > but without someone who tests there's not much I can do, so will just go
> > > ahead and apply and hope it works.
> >
> > Ok I went ahead and pushed a slight revised version of that patch which
> > just unconditionally sends out the event. That's not correct, but at least
> > that way the nonblocking changes won't totally break arcpgu and I can move
> > ahead with those.
> 
> Thanks for that.
> In the meantime I tried previously sent patches:
> --------------->8-------------
> 9267484 drm/arc: Actually bother with handling atomic events.
> cf4a489 drm/arc: Nuke event_list
> 9c3152e drm/atomic-helper: Massage swap_state signature somewhat
> --------------->8-------------
> and on both boards (axs103 and nSIM OSCI) video works quite fine.

The possible breakage only starts when you move further into the series,
up to patch 10. That implements generic nonblocking commit, but that
support relies upon crtc_state->event being signalled. Anyway I'm pulling
it all into drm-misc now, so you can just test that branch (or linux-next
when it's rebuild next week).
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch