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Merge tag 'drm-intel-next-fixes-2024-07-18' of https://gitlab.freedesktop.org/drm/i915/kernel into drm-next

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- Reset intel_dp->link_trained before retraining the link [dp] (Imre Deak)
- Don't switch the LTTPR mode on an active link [dp] (Imre Deak)

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Tvrtko Ursulin <tursulin@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ZpjgtowjpUZoHvrl@linux
This commit is contained in:
Dave Airlie 2024-07-22 10:51:47 +10:00
commit 7d4ecf3707
2 changed files with 50 additions and 7 deletions
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2
drivers/gpu/drm/i915/display/intel_dp.c
View File

@ -5314,6 +5314,8 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder,
const struct intel_crtc_state *crtc_state =
to_intel_crtc_state(crtc->base.state);
intel_dp->link_trained = false;
intel_dp_check_frl_training(intel_dp);
intel_dp_pcon_dsc_configure(intel_dp, crtc_state);
intel_dp_start_link_train(NULL, intel_dp, crtc_state);

55
drivers/gpu/drm/i915/display/intel_dp_link_training.c
View File

@ -117,10 +117,24 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable)
return drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) == 1;
}
static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
{
return intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] ==
DP_PHY_REPEATER_MODE_TRANSPARENT;
}
/*
* Read the LTTPR common capabilities and switch the LTTPR PHYs to
* non-transparent mode if this is supported. Preserve the
* transparent/non-transparent mode on an active link.
*
* Return the number of detected LTTPRs in non-transparent mode or 0 if the
* LTTPRs are in transparent mode or the detection failed.
*/
static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
int lttpr_count;
int i;
if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))
return 0;
@ -134,6 +148,19 @@ static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEI
if (lttpr_count == 0)
return 0;
/*
* Don't change the mode on an active link, to prevent a loss of link
* synchronization. See DP Standard v2.0 3.6.7. about the LTTPR
* resetting its internal state when the mode is changed from
* non-transparent to transparent.
*/
if (intel_dp->link_trained) {
if (lttpr_count < 0 || intel_dp_lttpr_transparent_mode_enabled(intel_dp))
goto out_reset_lttpr_count;
return lttpr_count;
}
/*
* See DP Standard v2.0 3.6.6.1. about the explicit disabling of
* non-transparent mode and the disable->enable non-transparent mode
@ -154,11 +181,25 @@ static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEI
"Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");
intel_dp_set_lttpr_transparent_mode(intel_dp, true);
intel_dp_reset_lttpr_count(intel_dp);
return 0;
goto out_reset_lttpr_count;
}
return lttpr_count;
out_reset_lttpr_count:
intel_dp_reset_lttpr_count(intel_dp);
return 0;
}
static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
int lttpr_count;
int i;
lttpr_count = intel_dp_init_lttpr_phys(intel_dp, dpcd);
for (i = 0; i < lttpr_count; i++)
intel_dp_read_lttpr_phy_caps(intel_dp, dpcd, DP_PHY_LTTPR(i));
@ -1482,10 +1523,10 @@ void intel_dp_start_link_train(struct intel_atomic_state *state,
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
struct intel_encoder *encoder = &dig_port->base;
bool passed;
/*
* TODO: Reiniting LTTPRs here won't be needed once proper connector
* HW state readout is added.
* Reinit the LTTPRs here to ensure that they are switched to
* non-transparent mode. During an earlier LTTPR detection this
* could've been prevented by an active link.
*/
int lttpr_count = intel_dp_init_lttpr_and_dprx_caps(intel_dp);