On Mon, Dec 15, 2014 at 03:22:08PM +0100, Daniel Vetter wrote: > On Mon, Dec 15, 2014 at 12:47:14PM +0000, Michel Thierry wrote: > > On 12/15/2014 10:11 AM, Daniel Vetter wrote: > > >On Thu, Dec 11, 2014 at 12:07:18PM +0000, Michel Thierry wrote: > > >>When execlists submission is enabled, try full ppgtt by default. > > >> > > >>Note, this patch considers that execlist support has been enabled by > > >>default on Gen8. > > >> > > >>Signed-off-by: Michel Thierry <[email protected]> > > >>--- > > >> drivers/gpu/drm/i915/i915_gem_gtt.c | 9 ++++++--- > > >> 1 file changed, 6 insertions(+), 3 deletions(-) > > >> > > >>diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c > > >>b/drivers/gpu/drm/i915/i915_gem_gtt.c > > >>index 171f6ea..4ed3904 100644 > > >>--- a/drivers/gpu/drm/i915/i915_gem_gtt.c > > >>+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c > > >>@@ -40,8 +40,8 @@ static int sanitize_enable_ppgtt(struct drm_device > > >>*dev, int enable_ppgtt) > > >> has_aliasing_ppgtt = INTEL_INFO(dev)->gen >= 6; > > >> has_full_ppgtt = INTEL_INFO(dev)->gen >= 7; > > >>- if (IS_GEN8(dev)) > > >>- has_full_ppgtt = false; /* XXX why? */ > > >>+ if (IS_GEN8(dev) && !i915.enable_execlists) > > >>+ has_full_ppgtt = false; /* Only enforce with execlists */ > > >Imo this has outlived it's usefulness - enable_ppgtt is an unsafe > > >parameter so everyone setting it themselves gets what they need. > > >Afair this was just because of the execlist depency on gen8 for ppgtt. > > >-Daniel > > Not sure if I'm following you up on this... > > The aim was to change the default value to _full_ only when execlists are > > also enable (after Thomas' patch). In gen8, we don't want to have full > > ppgtt with legacy ring submission. > > Yeah I gotten confused. The comment is a bit misleading thought, maybe > "Full ppgtt needs execlist since otherwise the ctx switch can hang"?
Actually I wasnt' confused: gen8+ has full ppgtt, like gen7. It's broken without execlist though, so what we should do is just change the default below. Otherwise if a user explicitly sets execlist=0 and ppgtt=2 we won't obey that, which doesn't make sense - for isolating bugs this might be a valid testcase (even when we know there's problems). So your patch should do two things: - Generally allow full ppgtt on gen8 - the current restriction doesn't make sense. - Switch the default to full ppgtt when execlist is enabled on gen8+, leave the default to aliasing/disabled everywhere else as is. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
