On Mon, 16 Mar 2020, Mario Kleiner <mario.kleiner.de@xxxxxxxxx> wrote: > This fixes a problem found on the MacBookPro 2017 Retina panel. > > The panel reports 10 bpc color depth in its EDID, and the > firmware chooses link settings at boot which support enough > bandwidth for 10 bpc (324000 kbit/sec = multiplier 0xc), > but the DP_MAX_LINK_RATE dpcd register only reports > 2.7 Gbps (multiplier value 0xa) as possible, in direct > contradiction of what the firmware successfully set up. > > This restricts the panel to 8 bpc, not providing the full > color depth of the panel. > > This patch adds a quirk specific to the MBP 2017 15" Retina > panel to add the additiional 324000 kbps link rate during > edp setup. > > Link to previous discussion of a different attempted fix > with Ville and Jani: > > https://patchwork.kernel.org/patch/11325935/ > > v2: Follow Jani's proposal of defining quirk_rates[] instead > of just appending 324000. This for better clarity. > > v3: Rebased onto current drm-tip, as of 16-March-2020. Adapt > to new edid_quirks parameter of drm_dp_has_quirk(). > > Signed-off-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx> > Tested-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> Pushed to drm-intel-next-queued, thanks for the patch. BR, Jani. > --- > drivers/gpu/drm/drm_dp_helper.c | 2 ++ > drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++++ > include/drm/drm_dp_helper.h | 7 +++++++ > 3 files changed, 20 insertions(+) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index c6fbe6e6bc9d..8ba4531e808d 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -1238,6 +1238,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = { > { OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'), false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) }, > /* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */ > { OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) }, > + /* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low DP_MAX_LINK_RATE */ > + { OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false, BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) }, > }; > > #undef OUI > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index 0a417cd2af2b..ef2e06e292d5 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -164,6 +164,17 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp) > }; > int i, max_rate; > > + if (drm_dp_has_quirk(&intel_dp->desc, 0, > + DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS)) { > + /* Needed, e.g., for Apple MBP 2017, 15 inch eDP Retina panel */ > + static const int quirk_rates[] = { 162000, 270000, 324000 }; > + > + memcpy(intel_dp->sink_rates, quirk_rates, sizeof(quirk_rates)); > + intel_dp->num_sink_rates = ARRAY_SIZE(quirk_rates); > + > + return; > + } > + > max_rate = drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]); > > for (i = 0; i < ARRAY_SIZE(dp_rates); i++) { > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index c6119e4c169a..9d87cdf2740a 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1548,6 +1548,13 @@ enum drm_dp_quirk { > * capabilities advertised. > */ > DP_QUIRK_FORCE_DPCD_BACKLIGHT, > + /** > + * @DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS: > + * > + * The device supports a link rate of 3.24 Gbps (multiplier 0xc) despite > + * the DP_MAX_LINK_RATE register reporting a lower max multiplier. > + */ > + DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS, > }; > > /** -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
