On Thu, Aug 14, 2014 at 10:12:06AM -0400, Jerome Glisse wrote: > On Thu, Aug 14, 2014 at 09:16:02AM -0400, Rob Clark wrote: > > On Wed, Aug 13, 2014 at 1:07 PM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote: > > > So this is fundamentaly different, fence as they are now allow random driver > > > callback and this is bound to get ugly this is bound to lead to one driver > > > doing something that seems innocuous but turn out to break heavoc when call > > > from some other driver function. > > > > > > tbh, that seems solvable by some strict rules about what you can do in > > the callback.. ie. don't do anything you couldn't do in atomic, and > > don't signal another fence.. off the top of my head that seems > > sufficient. > > > > If the driver getting the callback needs to do more, then it can > > always schedule a worker.. > > > > But I could certainly see the case where the driver waiting on fence > > sets everything up before installing the cb and then just needs to > > write one or a couple regs from the cb. > > Yes sane code will do sane things, sadly i fear we can not enforce sane > code everywhere especialy with out of tree driver and i would rather > force there hand to only allow sane implementation. Providing call back > api obviously allows them to do crazy stuff. Well then don't support out of tree drivers. Fairly easy problem really, and last time I checked "out of tree drivers suck" isn't a valid objections for upstream code ... It's kinda assumed that they all do, it's why we have staging after all. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
