[PATCH 3/4] drm/i915/psr: Apply Intel DPCD workaround when SDP on prior line used

Jouni Högander
2026-04-15T05:40:32Z

There is Intel specific workaround DPCD address containing workaround for
case where SDP is on prior line. Apply this workaround according to values
in the offset.

Fixes: 61e887329e33 ("drm/i915/xelpd: Handle PSR2 SDP indication in the prior scanline")
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
---
drivers/gpu/drm/i915/display/intel_psr.c | 36 +++++++++++++++++++++---
1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 1f3f0d35d52a..341186622ed4 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1385,9 +1385,36 @@ static bool psr2_granularity_check(struct intel_crtc_state *crtc_state,
return true;
}

-static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_dp,
- struct intel_crtc_state *crtc_state)
+static bool apply_scanline_indication_wa(struct intel_crtc_state *crtc_state,
+ struct intel_connector *connector)
{
+ struct intel_dp *intel_dp = intel_attached_dp(connector);
+ u8 early_scanline_support = connector->dp.psr_caps.intel_wa_dpcd &
+ INTEL_WA_REGISTER_CAPS_PSR2_EARLYSCANLINE_SDP_SUPPORT_MASK;
+
+ if (intel_dp->edp_dpcd[0] >= DP_EDP_15)
+ return true;
+
+ switch(early_scanline_support)
+ {
+ case INTEL_WA_REGISTER_CAPS_FALL_BACK_TO_PSR1:
+ crtc_state->req_psr2_sdp_prior_scanline = false;
+ return false;
+ case INTEL_WA_REGISTER_CAPS_PSR2_WITH_EARLY_SCANLINE:
+ return true;
+ case INTEL_WA_REGISTER_CAPS_PSR2_WITHOUT_EARLY_SCANLINE:
+ crtc_state->req_psr2_sdp_prior_scanline = false;
+ return true;
+ default:
+ MISSING_CASE(early_scanline_support);
+ return false;
+ }
+}
+
+static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_crtc_state *crtc_state,
+ struct intel_connector *connector)
+{
+ struct intel_dp *intel_dp = intel_attached_dp(connector);
struct intel_display *display = to_intel_display(intel_dp);
const struct drm_display_mode *adjusted_mode = &crtc_state->uapi.adjusted_mode;
u32 hblank_total, hblank_ns, req_ns;
@@ -1406,7 +1433,8 @@ static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_d
return false;

crtc_state->req_psr2_sdp_prior_scanline = true;
- return true;
+
+ return apply_scanline_indication_wa(crtc_state, connector);
}

static int intel_psr_entry_setup_frames(struct intel_dp *intel_dp,
@@ -1687,7 +1715,7 @@ static bool intel_sel_update_config_valid(struct intel_crtc_state *crtc_state,
conn_state))
goto unsupported;

- if (!_compute_psr2_sdp_prior_scanline_indication(intel_dp, crtc_state)) {
+ if (!_compute_psr2_sdp_prior_scanline_indication(crtc_state, connector)) {
drm_dbg_kms(display->drm,
"Selective update not enabled, SDP indication do not fit in hblank\n");
goto unsupported;
--
2.43.0