On Sat, Jun 29, 2013 at 02:20:40PM -0700, Ben Widawsky wrote: > On Sat, Jun 29, 2013 at 04:38:00PM +0200, Daniel Vetter wrote: > > On Sat, Jun 29, 2013 at 12:23 AM, Ben Widawsky <ben at bwidawsk.net> wrote: > > > 2. echo 2 > /sys/kernel/debug/dri/0/i915_debug_flags > > > Unbind all buffers synchronously, so any batch which has bad code will fault > > > every time and not get lucky by hitting a buffer it bound. This will not catch > > > cases where it accidentally reads/writes someone else's buffer. > > > > We already have this as the drop_caches debugfs interface. Chris used > > it to reproduce the 3.7 reloc-tree regression, the only downside is > > that no one ever got around to write the respective i-g-t ... :( > > -Daniel > > In order to achieve the same behavior, one must instrument every GPU > client to use that interface before, and after every batch (you can skip > one if you're positive all clients have opted in). Also, every client > must be run as root. > > This mechanism I've introduced is much simpler to achieve the intended > result. Oh right, your patch is doing something else completely. One thing which would be neat on top of this is to randomize the locations of each bo a bit (varibale padding in front should be good enough). That way we can check whether the relocations are all handled properly. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
