Re: [PATCH 8/9] drm/i915/wm: Include ddb_y in skl_print_wm_changes() on pre-icl

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Mar 19, 2026 at 03:44:29PM +0200, Jani Nikula wrote:
> On Thu, 19 Mar 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Pre-icl doesn't use a separate hardware plane for Y scanout,
> > and instead it's all handled magially by the hardware. We
> 
> *magically
> 
> > do still need to allocate DDB space for the Y color plane
> > though (PLANE_NV12_BUF_CFG). Include that information in the
> > debugs so that we know where it ended up.
> >
> > On icl+ the equivalent information is dumped as the hardware
> > Y plane's normal ddb allocation.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/skl_watermark.c | 11 +++++++++--
> >  1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c
> > index 8687026935e9..345767349988 100644
> > --- a/drivers/gpu/drm/i915/display/skl_watermark.c
> > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c
> > @@ -2735,10 +2735,17 @@ skl_print_wm_changes(struct intel_atomic_state *state)
> >  			old = &old_crtc_state->wm.skl.plane_ddb[plane_id];
> >  			new = &new_crtc_state->wm.skl.plane_ddb[plane_id];
> >  
> > -			if (skl_ddb_entry_equal(old, new))
> > +			if (!skl_ddb_entry_equal(old, new))
> > +				skl_print_plane_ddb_changes(plane, old, new, "  ddb");
> 
> Superfluous whitespace in "  ddb"?

It's there to align the columns in the "ddb" and "ddb_y" prints.
Perhaps I should use the printk field width for that instead...

> 
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> 
> 
> > +
> > +			if (DISPLAY_VER(display) >= 11)
> >  				continue;
> >  
> > -			skl_print_plane_ddb_changes(plane, old, new, "ddb");
> > +			old = &old_crtc_state->wm.skl.plane_ddb_y[plane_id];
> > +			new = &new_crtc_state->wm.skl.plane_ddb_y[plane_id];
> > +
> > +			if (!skl_ddb_entry_equal(old, new))
> > +				skl_print_plane_ddb_changes(plane, old, new, "ddb_y");
> >  		}
> >  
> >  		for_each_intel_plane_on_crtc(display->drm, crtc, plane) {
> 
> -- 
> Jani Nikula, Intel

-- 
Ville Syrjälä
Intel