On Wed, Apr 10, 2019 at 03:54:23PM +0300, Jani Nikula wrote:
> On Fri, 05 Apr 2019, Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> wrote:
> > On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> >> Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> >> and narrow") started to optize the eDP 1.4+ link config, both per spec
> >> and as preparation for display stream compression support.
> >>
> >> Sadly, we again face panels that flat out fail with parameters they
> >> claim to support. Revert, and go back to the drawing board.
> >>
> >> v2: Actually revert to max params instead of just wide-and-slow.
> >>
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> >> Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> >> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >> Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> >> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> >> Cc: Matt Atwood <matthew.s.atwood@xxxxxxxxx>
> >> Cc: "Lee, Shawn C" <shawn.c.lee@xxxxxxxxx>
> >> Cc: Dave Airlie <airlied@xxxxxxxxx>
> >> Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> >> Cc: <stable@xxxxxxxxxxxxxxx> # v5.0+
> >> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> >
> > I can hear from here your "I told you so"... Sorry!
> >
> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
>
> Thanks, pushed, please cherry-pick this for drm-intel-fixes.
done. going on tomorrow's pull request...
>
> BR,
> Jani.
>
>
>
> >
> >> ---
> >> drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
> >> 1 file changed, 10 insertions(+), 59 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >> index 72c490..dfa770 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >> return -EINVAL;
> >> }
> >>
> >> -/* Optimize link config in order: max bpp, min lanes, min clock */
> >> -static int
> >> -intel_dp_compute_link_config_fast(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 (lane_count = limits->min_lane_count;
> >> - lane_count <= limits->max_lane_count;
> >> - lane_count <<= 1) {
> >> - for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> >> - 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 0;
> >> - }
> >> - }
> >> - }
> >> - }
> >> -
> >> - return -EINVAL;
> >> -}
> >> -
> >> static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> >> {
> >> int i, num_bpc;
> >> @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >> limits.min_bpp = 6 * 3;
> >> limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> >>
> >> - if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> >> + if (intel_dp_is_edp(intel_dp)) {
> >> /*
> >> * Use the maximum clock and number of lanes the eDP panel
> >> - * advertizes being capable of. The eDP 1.3 and earlier panels
> >> - * are generally designed to support only a single clock and
> >> - * lane configuration, and typically these values correspond to
> >> - * the native resolution of the panel. With eDP 1.4 rate select
> >> - * and DSC, this is decreasingly the case, and we need to be
> >> - * able to select less than maximum link config.
> >> + * advertizes being capable of. The panels are generally
> >> + * designed to support only a single clock and lane
> >> + * configuration, and typically these values correspond to the
> >> + * native resolution of the panel.
> >> */
> >> limits.min_lane_count = limits.max_lane_count;
> >> limits.min_clock = limits.max_clock;
> >> @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >> intel_dp->common_rates[limits.max_clock],
> >> limits.max_bpp, adjusted_mode->crtc_clock);
> >>
> >> - if (intel_dp_is_edp(intel_dp))
> >> - /*
> >> - * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> >> - * section A.1: "It is recommended that the minimum number of
> >> - * lanes be used, using the minimum link rate allowed for that
> >> - * lane configuration."
> >> - *
> >> - * Note that we use the max clock and lane count for eDP 1.3 and
> >> - * earlier, and fast vs. wide is irrelevant.
> >> - */
> >> - ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> >> - &limits);
> >> - else
> >> - /* Optimize for slow and wide. */
> >> - ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> >> - &limits);
> >> + /*
> >> + * Optimize for slow and wide. This is the place to add alternative
> >> + * optimization policy.
> >> + */
> >> + ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
> >>
> >> /* enable compression if the mode doesn't fit available BW */
> >> DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> >> --
> >> 2.20.1
> >>
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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