On Tue, Oct 04, 2022 at 02:19:15PM +0100, Matthew Auld wrote: > For these types of display buffers, we need to able to CPU access some > part of the backing memory in prepare_plane_clear_colors(). As a result > we need to ensure we always place in the mappable part of lmem, which > becomes necessary on small-bar systems. > > v2(Nirmoy & Ville): > - Add some commentary for why we need to CPU access the buffer. > - Split out the other changes, so we just consider the display change > here. > v3: > - Handle this in the dpt path. > v4(Ville): > - Drop the intel_fb_rc_ccs_cc_plane() sanity check in > pin_and_fence_fb_obj(), since we can also trigger this on DG1 it > seems.
On some hw I think there was also a chicken bit to disable DPT, and the DPT simulation situation was always a mess (you had to enable it using some custom config). So in theory someone might have the need to use the non-DPT path on more modern hw as well, but I'm OK not considering it here. If someone thinks that small-bar+no-DPT is important they can deal with it in a separate patch. Reviewed-by: Ville Syrjälä <[email protected]> > > Fixes: eb1c535f0d69 ("drm/i915: turn on small BAR support") > Reported-by: Jianshui Yu <[email protected]> > Signed-off-by: Matthew Auld <[email protected]> > Cc: Ville Syrjälä <[email protected]> > Cc: Nirmoy Das <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_fb_pin.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c > b/drivers/gpu/drm/i915/display/intel_fb_pin.c > index 5031ee5695dd..e12339f46640 100644 > --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c > +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c > @@ -50,7 +50,18 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb, > continue; > > if (HAS_LMEM(dev_priv)) { > - ret = i915_gem_object_migrate(obj, &ww, > INTEL_REGION_LMEM_0); > + unsigned int flags = obj->flags; > + > + /* > + * For this type of buffer we need to able to read from > the CPU > + * the clear color value found in the buffer, hence we > need to > + * ensure it is always in the mappable part of lmem, if > this is > + * a small-bar device. > + */ > + if (intel_fb_rc_ccs_cc_plane(fb) >= 0) > + flags &= ~I915_BO_ALLOC_GPU_ONLY; > + ret = __i915_gem_object_migrate(obj, &ww, > INTEL_REGION_LMEM_0, > + flags); > if (ret) > continue; > } > -- > 2.37.3 -- Ville Syrjälä Intel
