Message ID | 20250108123541.2101643-7-mitulkumar.ajitkumar.golani@intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | Check Scaler and DSC Prefill Latency Against Vblank | expand |
On 1/8/2025 6:05 PM, Mitul Golani wrote: > Check if vblank is too short for scaler prefill latency. Perhaps we can elaborate a bit. Also add Bspec# in trailer. > > --v2: > - Use hweight* family of functions for counting bits. [Jani] > - Update precision handling for hscale and vscale. [Ankit] > - Consider chroma downscaling factor during latency > calculation. [Ankit] > - Replace function name from scaler_prefill_time to > scaler_prefill_latency. > > --v3: > - hscale_k and vscale_k values are already left shifted by 16, > after multiplying by 1000, those need to be right shifted to 16. [Ankit] > - Replace YCBCR444 to YCBCR420. [Ankit] > - Divide by 1000 * 1000 in end to get correct precision. [Ankit] > - Initialise latency to 0 to avoid any garbage. > > Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com> > --- > drivers/gpu/drm/i915/display/skl_watermark.c | 31 ++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c > index f4458d1185b3..fe91854e456c 100644 > --- a/drivers/gpu/drm/i915/display/skl_watermark.c > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c > @@ -2292,6 +2292,36 @@ static int icl_build_plane_wm(struct intel_crtc_state *crtc_state, > return 0; > } > > +static int > +scaler_prefill_latency(const struct intel_crtc_state *crtc_state) > +{ > + const struct intel_crtc_scaler_state *scaler_state = > + &crtc_state->scaler_state; > + int count = hweight32(scaler_state->scaler_users); > + int latency = 0; > + long long hscale_k = > + mul_u32_u32(scaler_state->scalers[0].hscale, 1000) >> 16; > + long long vscale_k = > + mul_u32_u32(scaler_state->scalers[0].vscale, 1000) >> 16; > + > + if (!count) > + return latency; > + > + if (count > 1) { > + int chroma_downscaling_factor = > + crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 ? 2 : 1; > + > + latency = (4 * crtc_state->linetime) + > + (chroma_downscaling_factor * > + DIV_ROUND_UP_ULL((4 * crtc_state->linetime * hscale_k * vscale_k), > + 1000000)); > + } else { > + latency = 4 * crtc_state->linetime; > + } > + > + return latency; > +} > + > static bool > skl_is_vblank_too_short(const struct intel_crtc_state *crtc_state, > int wm0_lines, int latency) > @@ -2302,6 +2332,7 @@ skl_is_vblank_too_short(const struct intel_crtc_state *crtc_state, > /* FIXME missing scaler and DSC pre-fill time */ The scaler part is addressed in this patch, so this can be removed. Regards, Ankit > return crtc_state->framestart_delay + > intel_usecs_to_scanlines(adjusted_mode, latency) + > + scaler_prefill_latency(crtc_state) + > wm0_lines > > adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vblank_start; > }
diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c index f4458d1185b3..fe91854e456c 100644 --- a/drivers/gpu/drm/i915/display/skl_watermark.c +++ b/drivers/gpu/drm/i915/display/skl_watermark.c @@ -2292,6 +2292,36 @@ static int icl_build_plane_wm(struct intel_crtc_state *crtc_state, return 0; } +static int +scaler_prefill_latency(const struct intel_crtc_state *crtc_state) +{ + const struct intel_crtc_scaler_state *scaler_state = + &crtc_state->scaler_state; + int count = hweight32(scaler_state->scaler_users); + int latency = 0; + long long hscale_k = + mul_u32_u32(scaler_state->scalers[0].hscale, 1000) >> 16; + long long vscale_k = + mul_u32_u32(scaler_state->scalers[0].vscale, 1000) >> 16; + + if (!count) + return latency; + + if (count > 1) { + int chroma_downscaling_factor = + crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 ? 2 : 1; + + latency = (4 * crtc_state->linetime) + + (chroma_downscaling_factor * + DIV_ROUND_UP_ULL((4 * crtc_state->linetime * hscale_k * vscale_k), + 1000000)); + } else { + latency = 4 * crtc_state->linetime; + } + + return latency; +} + static bool skl_is_vblank_too_short(const struct intel_crtc_state *crtc_state, int wm0_lines, int latency) @@ -2302,6 +2332,7 @@ skl_is_vblank_too_short(const struct intel_crtc_state *crtc_state, /* FIXME missing scaler and DSC pre-fill time */ return crtc_state->framestart_delay + intel_usecs_to_scanlines(adjusted_mode, latency) + + scaler_prefill_latency(crtc_state) + wm0_lines > adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vblank_start; }
Check if vblank is too short for scaler prefill latency. --v2: - Use hweight* family of functions for counting bits. [Jani] - Update precision handling for hscale and vscale. [Ankit] - Consider chroma downscaling factor during latency calculation. [Ankit] - Replace function name from scaler_prefill_time to scaler_prefill_latency. --v3: - hscale_k and vscale_k values are already left shifted by 16, after multiplying by 1000, those need to be right shifted to 16. [Ankit] - Replace YCBCR444 to YCBCR420. [Ankit] - Divide by 1000 * 1000 in end to get correct precision. [Ankit] - Initialise latency to 0 to avoid any garbage. Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com> --- drivers/gpu/drm/i915/display/skl_watermark.c | 31 ++++++++++++++++++++ 1 file changed, 31 insertions(+)