From 3acd115d08f70615debd5a8d37a8b97dc17a9cbb Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Thu, 26 Apr 2018 11:25:29 +0300 Subject: [PATCH] drm/i915/dp: abstract link config selection For now, there's just the one link config selection, optimizing for slow and wide link. No functional changes. Keep the debug logging in the caller, to avoid duplication later on if alternative link confing selection gets added. v2: Improved commit message Reviewed-by: Manasi Navare Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/64848b76bf90d6ceecd7ec6b5add28531e0b1a41.1524730974.git.jani.nikula@intel.com --- drivers/gpu/drm/i915/intel_dp.c | 81 ++++++++++++++++++++------------- 1 file changed, 50 insertions(+), 31 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 9ef29b63b237b..d622db76b9c3a 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1704,6 +1704,42 @@ static bool intel_edp_compare_alt_mode(struct drm_display_mode *m1, return bres; } +/* Optimize link config in order: max bpp, min clock, min lanes */ +static bool +intel_dp_compute_link_config_wide(struct intel_dp *intel_dp, + struct intel_crtc_state *pipe_config, + const struct link_config_limits *limits) +{ + struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode; + int bpp, clock, lane_count; + int mode_rate, link_clock, link_avail; + + for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) { + mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock, + bpp); + + for (clock = limits->min_clock; clock <= limits->max_clock; clock++) { + for (lane_count = limits->min_lane_count; + lane_count <= limits->max_lane_count; + lane_count <<= 1) { + link_clock = intel_dp->common_rates[clock]; + link_avail = intel_dp_max_data_rate(link_clock, + lane_count); + + if (mode_rate <= link_avail) { + pipe_config->lane_count = lane_count; + pipe_config->pipe_bpp = bpp; + pipe_config->port_clock = link_clock; + + return true; + } + } + } + } + + return false; +} + static bool intel_dp_compute_link_config(struct intel_encoder *encoder, struct intel_crtc_state *pipe_config) @@ -1711,8 +1747,6 @@ intel_dp_compute_link_config(struct intel_encoder *encoder, struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode; struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base); struct link_config_limits limits; - int bpp, clock, lane_count; - int mode_rate, link_avail, link_clock; int common_len; common_len = intel_dp_common_len_rate_limit(intel_dp, @@ -1766,37 +1800,22 @@ intel_dp_compute_link_config(struct intel_encoder *encoder, intel_dp->common_rates[limits.max_clock], limits.max_bpp, adjusted_mode->crtc_clock); - for (bpp = limits.max_bpp; bpp >= limits.min_bpp; bpp -= 2 * 3) { - mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock, - bpp); - - for (clock = limits.min_clock; clock <= limits.max_clock; clock++) { - for (lane_count = limits.min_lane_count; - lane_count <= limits.max_lane_count; - lane_count <<= 1) { - - link_clock = intel_dp->common_rates[clock]; - link_avail = intel_dp_max_data_rate(link_clock, - lane_count); - - if (mode_rate <= link_avail) { - goto found; - } - } - } - } - - return false; - -found: - pipe_config->lane_count = lane_count; - pipe_config->pipe_bpp = bpp; - pipe_config->port_clock = intel_dp->common_rates[clock]; + /* + * Optimize for slow and wide. This is the place to add alternative + * optimization policy. + */ + if (!intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits)) + return false; DRM_DEBUG_KMS("DP lane count %d clock %d bpp %d\n", - pipe_config->lane_count, pipe_config->port_clock, bpp); - DRM_DEBUG_KMS("DP link bw required %i available %i\n", - mode_rate, link_avail); + pipe_config->lane_count, pipe_config->port_clock, + pipe_config->pipe_bpp); + + DRM_DEBUG_KMS("DP link rate required %i available %i\n", + intel_dp_link_required(adjusted_mode->crtc_clock, + pipe_config->pipe_bpp), + intel_dp_max_data_rate(pipe_config->port_clock, + pipe_config->lane_count)); return true; } -- 2.30.2