On Tue, 04 Sep 2018, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > Quoting Lee, Shawn C (2018-09-04 15:55:41) >> eDP 1.4 introduce a new link rates flexibility and selection. >> It provided system specific link rate optimization and power >> efficiency. We should keep eDP 1.3 and older version to use >> max link rate approach to avoid any side effect. And eDP 1.4 >> used the optimization link rate and lane count setting. >> >> Cc: Matt Atwood <matthew.s.atwood@xxxxxxxxx> >> Signed-off-by: Lee, Shawn C <shawn.c.lee@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/intel_dp.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c >> index 436c22de33b6..903d640fe712 100644 >> --- a/drivers/gpu/drm/i915/intel_dp.c >> +++ b/drivers/gpu/drm/i915/intel_dp.c >> @@ -1953,8 +1953,10 @@ intel_dp_compute_link_config(struct intel_encoder *encoder, >> * configuration, and typically these values correspond to the >> * native resolution of the panel. >> */ > > Having just finished a comment explaining why we override the limits for > eDP, the following logic is confusing without at least a mention above. I think the proper approach with the appropriate explanations is [1]. I think it's harmful to start optimizing on eDP 1.4 without also optimizing for fast and narrow link per spec at the same time. BR, Jani. [1] http://patchwork.freedesktop.org/patch/msgid/20180905095321.13843-1-jani.nikula@xxxxxxxxx > >> - limits.min_lane_count = limits.max_lane_count; >> - limits.min_clock = limits.max_clock; >> + if (intel_dp->edp_dpcd[0] <= DP_EDP_13) { >> + limits.min_lane_count = limits.max_lane_count; >> + limits.min_clock = limits.max_clock; >> + } >> } >> >> intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits); >> -- >> 2.7.4 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
