| Message ID | 20210818171457.536107-1-kai.heng.feng@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/i915/dp: Use max params for panels < eDP 1.4 | expand |
On Thu, Aug 19, 2021 at 01:14:55AM +0800, Kai-Heng Feng wrote: > Users reported that after commit 2bbd6dba84d4 ("drm/i915: Try to use > fast+narrow link on eDP again and fall back to the old max strategy on > failure"), the screen starts to have wobbly effect. > > Commit a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for > everything") doesn't help either, that means the affected eDP 1.2 panels > only work with max params. > > So use max params for panels < eDP 1.4 as Windows does to solve the > issue. > > v2: > - Check eDP 1.4 instead of DPCD 1.1 to apply max params > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3714 > Fixes: 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure") > Fixes: a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") > Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 75d4ebc669411..f87fad78f1a9f 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -1330,14 +1330,16 @@ intel_dp_compute_link_config(struct intel_encoder *encoder, > limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format); > limits.max_bpp = intel_dp_max_bpp(intel_dp, pipe_config); > > - if (intel_dp->use_max_params) { > + if (intel_dp->use_max_params || > + intel_dp->edp_dpcd[0] < DP_EDP_14) { I think we're going to need a is_edp check here or else we'll always take this path on extenral DP when edp_dpcd[] is zeroed. Hmm. Maybe just stick intel_dp->use_max_params = intel_dp->edp_dpcd[0] < DP_EDP_14; into intel_edp_init_dpcd()? > /* > * Use the maximum clock and number of lanes the eDP panel > * advertizes being capable of in case the initial fast > - * optimal params failed us. The panels are generally > - * designed to support only a single clock and lane > - * configuration, and typically on older panels these > - * values correspond to the native resolution of the panel. > + * optimal params failed us or the EDP rev is earlier than 1.4. > + * The panels are generally designed to support only a single > + * clock and lane configuration, and typically on older panels > + * these values correspond to the native resolution of the > + * panel. > */ > limits.min_lane_count = limits.max_lane_count; > limits.min_clock = limits.max_clock; > -- > 2.32.0
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 75d4ebc669411..f87fad78f1a9f 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -1330,14 +1330,16 @@ intel_dp_compute_link_config(struct intel_encoder *encoder, limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format); limits.max_bpp = intel_dp_max_bpp(intel_dp, pipe_config); - if (intel_dp->use_max_params) { + if (intel_dp->use_max_params || + intel_dp->edp_dpcd[0] < DP_EDP_14) { /* * Use the maximum clock and number of lanes the eDP panel * advertizes being capable of in case the initial fast - * optimal params failed us. The panels are generally - * designed to support only a single clock and lane - * configuration, and typically on older panels these - * values correspond to the native resolution of the panel. + * optimal params failed us or the EDP rev is earlier than 1.4. + * The panels are generally designed to support only a single + * clock and lane configuration, and typically on older panels + * these values correspond to the native resolution of the + * panel. */ limits.min_lane_count = limits.max_lane_count; limits.min_clock = limits.max_clock;
Users reported that after commit 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure"), the screen starts to have wobbly effect. Commit a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") doesn't help either, that means the affected eDP 1.2 panels only work with max params. So use max params for panels < eDP 1.4 as Windows does to solve the issue. v2: - Check eDP 1.4 instead of DPCD 1.1 to apply max params Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3714 Fixes: 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure") Fixes: a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> --- drivers/gpu/drm/i915/display/intel_dp.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)