On Fri, Sep 12, 2014 at 01:03:51PM -0400, Peter Hurley wrote: > On 09/12/2014 12:04 PM, Chris Wilson wrote: > > On Fri, Sep 12, 2014 at 05:34:56PM +0200, Daniel Vetter wrote: > >> On Fri, Sep 12, 2014 at 04:23:29PM +0100, Chris Wilson wrote: > >>> On Fri, Sep 12, 2014 at 03:40:56PM +0200, Daniel Vetter wrote: > >>>> The comment says that the caller must hold the dev->event_lock > >>>> spinlock, so let's enforce this. > >>>> > >>>> A quick audit over all driver shows that except for the one place in > >>>> i915 which motivated this all callers fullfill this requirement > >>>> already. > >>> > >>> Replace the rogue WARN_ON_SMP(!spin_is_locked(&dev->event_lock)) in > >>> send_vblank_event() as well then. > >> > >> Meh, I've missed that one, that's actually better I think. I'll drop my > >> patch here. > > > > I thought assert_spin_lock was the preferred form? > > Actually, lockdep_assert_held() is the preferred form. > > See https://lkml.org/lkml/2014/9/3/171 Which unfortunately doesn't warn for all the normal users which are not insane enough to enable lockdep and so is totally useless to validate a driver that runs on metric piles of different chips (with a resulting combinatorial explosion of code-paths because hw designers are creative). And we rely a lot on random drive-by testers to report such issues. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
