On Thu, Apr 05, 2018 at 05:39:04PM +0300, Jani Nikula wrote:
> For now, there's just the one link config selection, optimizing for slow
> and wide link. No functional changes.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> 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 3c5fbdf42b9b..c98626b3af65 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));
Wouldnt it be better if we move this Debug message about Available and
required link rate in the other function right after the condition
if (mode_rate <= link_avail) is true, before returning true from that function.
I think it will be just more intuitive there.
Everything else looks good. So
Reviewed-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
Manasi
>
> return true;
> }
> --
> 2.11.0
>
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