On Mon, Oct 13, 2025 at 06:30:20PM +0000, Shankar, Uma wrote: > > > > -----Original Message----- > > From: Intel-gfx <[email protected]> On Behalf Of Ville > > Syrjala > > Sent: Wednesday, October 8, 2025 11:56 PM > > To: [email protected] > > Cc: [email protected] > > Subject: [RFC][PATCH 06/11] drm/i195/wm: Add WM0 prefill helpers > > > > Nit: Typo in i915 > > Overall looks good to me. More refinement can be done later for the FIXME's > and Todo's
Actually I think I can just drop a bunch of it since this will only get used for the VRR guardband calculation, so we definitely don't have to worry about any pre-icl stuff here. I'll probably throw in a WARN(!HAS_VRR)+comment as a reminder. > Reviewed-by: Uma Shankar <[email protected]> > > > From: Ville Syrjälä <[email protected]> > > > > Add skl_wm0_prefill_lines() (based on the actual state) and > > skl_wm0_prefill_lines_worst() (worst case estimate) which tell us how many > > extra > > lines are needed in prefill for WM0. > > > > The returned numbers are in .16 binary fixed point. > > > > TODO: skl_wm0_prefill_lines_worst() is a bit rough still > > > > Signed-off-by: Ville Syrjälä <[email protected]> > > --- > > drivers/gpu/drm/i915/display/skl_scaler.c | 32 ++++++++++- > > drivers/gpu/drm/i915/display/skl_scaler.h | 4 ++ > > drivers/gpu/drm/i915/display/skl_watermark.c | 59 ++++++++++++++++++++ > > drivers/gpu/drm/i915/display/skl_watermark.h | 3 + > > 4 files changed, 97 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/display/skl_scaler.c > > b/drivers/gpu/drm/i915/display/skl_scaler.c > > index 6e90639494ca..783fee985e84 100644 > > --- a/drivers/gpu/drm/i915/display/skl_scaler.c > > +++ b/drivers/gpu/drm/i915/display/skl_scaler.c > > @@ -1089,7 +1089,37 @@ static unsigned int _skl_scaler_max_scale(const > > struct intel_crtc_state *crtc_st > > crtc_state- > > >hw.pipe_mode.crtc_clock)); > > } > > > > -static unsigned int skl_scaler_max_scale(const struct intel_crtc_state > > *crtc_state) > > +unsigned int skl_scaler_max_total_scale(const struct intel_crtc_state > > +*crtc_state) { > > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc); > > + unsigned int max_scale; > > + > > + if (crtc->num_scalers < 1) > > + return 0x10000; > > + > > + /* FIXME find out the max downscale factors properly */ > > + max_scale = 9 << 16; > > + if (crtc->num_scalers > 1) > > + max_scale *= 9; > > + > > + return _skl_scaler_max_scale(crtc_state, max_scale); } > > + > > +unsigned int skl_scaler_max_hscale(const struct intel_crtc_state > > +*crtc_state) { > > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc); > > + unsigned int max_scale; > > + > > + if (crtc->num_scalers < 1) > > + return 0x10000; > > + > > + /* FIXME find out the max downscale factors properly */ > > + max_scale = 3 << 16; > > + > > + return _skl_scaler_max_scale(crtc_state, max_scale); } > > + > > +unsigned int skl_scaler_max_scale(const struct intel_crtc_state > > +*crtc_state) > > { > > struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc); > > unsigned int max_scale; > > diff --git a/drivers/gpu/drm/i915/display/skl_scaler.h > > b/drivers/gpu/drm/i915/display/skl_scaler.h > > index 6fab40d2b4ee..5deabca909e6 100644 > > --- a/drivers/gpu/drm/i915/display/skl_scaler.h > > +++ b/drivers/gpu/drm/i915/display/skl_scaler.h > > @@ -46,6 +46,10 @@ void adl_scaler_ecc_mask(const struct intel_crtc_state > > *crtc_state); > > > > void adl_scaler_ecc_unmask(const struct intel_crtc_state *crtc_state); > > > > +unsigned int skl_scaler_max_total_scale(const struct intel_crtc_state > > +*crtc_state); unsigned int skl_scaler_max_scale(const struct > > +intel_crtc_state *crtc_state); unsigned int skl_scaler_max_hscale(const > > +struct intel_crtc_state *crtc_state); > > + > > unsigned int skl_scaler_1st_prefill_adjustment_worst(const struct > > intel_crtc_state > > *crtc_state); unsigned int skl_scaler_2nd_prefill_adjustment_worst(const > > struct > > intel_crtc_state *crtc_state); unsigned int > > skl_scaler_1st_prefill_lines_worst(const struct intel_crtc_state > > *crtc_state); diff -- > > git a/drivers/gpu/drm/i915/display/skl_watermark.c > > b/drivers/gpu/drm/i915/display/skl_watermark.c > > index 9df9ee137bf9..aac3ca8f6c0f 100644 > > --- a/drivers/gpu/drm/i915/display/skl_watermark.c > > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c > > @@ -29,6 +29,7 @@ > > #include "intel_pcode.h" > > #include "intel_plane.h" > > #include "intel_wm.h" > > +#include "skl_scaler.h" > > #include "skl_universal_plane_regs.h" > > #include "skl_watermark.h" > > #include "skl_watermark_regs.h" > > @@ -2244,6 +2245,59 @@ skl_is_vblank_too_short(const struct intel_crtc_state > > *crtc_state, > > adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vblank_start; > > } > > > > +unsigned int skl_wm0_prefill_lines_worst(const struct intel_crtc_state > > +*crtc_state) { > > + struct intel_display *display = to_intel_display(crtc_state); > > + struct intel_plane *plane = > > to_intel_plane(crtc_state->uapi.crtc->primary); > > + const struct drm_display_mode *pipe_mode = &crtc_state- > > >hw.pipe_mode; > > + int ret, pixel_rate, width, level = 0; > > + struct skl_wm_level wm = {}; > > + struct skl_wm_params wp; > > + unsigned int latency; > > + u64 modifier; > > + > > + /* > > + * FIXME rather ugly to pick this by hand but maybe no other way? > > + * FIXME older hw doesn't support 16bpc+scaling so we should figure > > + * out a more realistic modifier+scaling combo on those... > > + */ > > + if (DISPLAY_VER(display) == 9) > > + modifier = I915_FORMAT_MOD_Y_TILED_CCS; > > + else if (HAS_4TILE(display)) > > + modifier = I915_FORMAT_MOD_4_TILED; > > + else > > + modifier = I915_FORMAT_MOD_Y_TILED; > > + > > + pixel_rate = > > DIV_ROUND_UP_ULL(mul_u32_u32(skl_scaler_max_total_scale(crtc_state), > > + pipe_mode->crtc_clock), > > + 0x10000); > > + > > + /* FIXME limit to max plane width? */ > > + width = > > DIV_ROUND_UP_ULL(mul_u32_u32(skl_scaler_max_hscale(crtc_state), > > + pipe_mode->crtc_hdisplay), > > + 0x10000); > > + > > + /* FIXME is 90/270 rotation worse than 0/180? */ > > + ret = skl_compute_wm_params(crtc_state, width, > > + > > drm_format_info(DRM_FORMAT_XBGR16161616F), > > + modifier, DRM_MODE_ROTATE_0, > > + pixel_rate, &wp, 0, 1); > > + drm_WARN_ON(display->drm, ret); > > + > > + latency = skl_wm_latency(display, level, &wp); > > + > > + skl_compute_plane_wm(crtc_state, plane, level, latency, &wp, &wm, > > +&wm); > > + > > + /* > > + * FIXME Is this sane? Older hw doesn't even have wm.lines for WM0 so > > + * those will never hit this and just return the computed wm.lines. > > + */ > > + if (wm.min_ddb_alloc == U16_MAX) > > + wm.lines = skl_wm_max_lines(display); > > + > > + return wm.lines << 16; > > +} > > + > > static int skl_max_wm0_lines(const struct intel_crtc_state *crtc_state) { > > struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc); > > @@ -2260,6 +2314,11 @@ static int skl_max_wm0_lines(const struct > > intel_crtc_state *crtc_state) > > return wm0_lines; > > } > > > > +unsigned int skl_wm0_prefill_lines(const struct intel_crtc_state > > +*crtc_state) { > > + return skl_max_wm0_lines(crtc_state) << 16; } > > + > > /* > > * TODO: In case we use PKG_C_LATENCY to allow C-states when the delayed > > vblank > > * size is too small for the package C exit latency we need to notify PSR > > about > > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.h > > b/drivers/gpu/drm/i915/display/skl_watermark.h > > index 62790816f030..6bc2ec9164bf 100644 > > --- a/drivers/gpu/drm/i915/display/skl_watermark.h > > +++ b/drivers/gpu/drm/i915/display/skl_watermark.h > > @@ -79,5 +79,8 @@ void intel_program_dpkgc_latency(struct intel_atomic_state > > *state); > > > > bool intel_dbuf_pmdemand_needs_update(struct intel_atomic_state *state); > > > > +unsigned int skl_wm0_prefill_lines_worst(const struct intel_crtc_state > > +*crtc_state); unsigned int skl_wm0_prefill_lines(const struct > > +intel_crtc_state *crtc_state); > > + > > #endif /* __SKL_WATERMARK_H__ */ > > > > -- > > 2.49.1 > -- Ville Syrjälä Intel
