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 <[email protected]> --- 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 */ 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; } -- 2.46.0
