[PATCH 08/13] drm/msm/dp: Rebuild the eDP stream on modesets leaving self refresh

[Xilin Wu]

The atomic helpers skip bridge disable when an active CRTC leaves self
refresh. The eDP enable callback also takes a fast path that only exits
PSR, so a concurrent modeset can leave the retained stream using its old
configuration, including the output depth.

Exit PSR and tear down the retained stream in pre-enable when leaving self
refresh with mode_changed or connectors_changed set. Install the new state
and run the normal stream enable sequence afterwards. Keep the fast path
for ordinary self-refresh exits: active_changed alone does not require
rebuilding the stream.

Assisted-by: LLM
Signed-off-by: Xilin Wu <sophon@xxxxxxxxx>
---
 drivers/gpu/drm/msm/dp/dp_drm.c   | 24 +++++++++++++++++++++++-
 drivers/gpu/drm/msm/dp/dp_utils.c |  7 +++++++
 drivers/gpu/drm/msm/dp/dp_utils.h |  4 ++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index c1e4147bfef1..7332fbfe1644 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -14,6 +14,7 @@
 #include "msm_kms.h"
 #include "dp_audio.h"
 #include "dp_drm.h"
+#include "dp_utils.h"
 
 /**
  * msm_dp_bridge_get_modes - callback to add drm modes via drm_mode_probed_add()
@@ -54,6 +55,26 @@ static void msm_dp_bridge_atomic_pre_enable(struct drm_bridge *drm_bridge,
 {
 	struct msm_dp_bridge *dp_bridge = to_dp_bridge(drm_bridge);
 	struct msm_dp *dp = dp_bridge->msm_dp_display;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
+
+	crtc = drm_atomic_get_new_crtc_for_encoder(state, drm_bridge->encoder);
+	if (!crtc)
+		return;
+
+	old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
+	new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+	/*
+	 * The helpers skip bridge disable when waking an active CRTC from
+	 * self refresh, even when its color configuration requires a modeset.
+	 * Tear down the retained stream before installing the new state.
+	 */
+	if (dp->is_edp && dp->power_on && old_crtc_state->self_refresh_active &&
+	    new_crtc_state->active && msm_dp_utils_psr_needs_modeset(new_crtc_state)) {
+		msm_dp_display_set_psr(dp, false);
+		msm_dp_display_atomic_disable(dp);
+		msm_dp_display_atomic_post_disable(dp);
+	}
 
 	msm_dp_display_atomic_pre_enable(dp, state);
 }
@@ -157,7 +178,8 @@ static void msm_edp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 
 	old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
 
-	if (old_crtc_state && old_crtc_state->self_refresh_active) {
+	if (dp->power_on && old_crtc_state && old_crtc_state->self_refresh_active &&
+	    !msm_dp_utils_psr_needs_modeset(drm_atomic_get_new_crtc_state(state, crtc))) {
 		msm_dp_display_set_psr(dp, false);
 		return;
 	}
diff --git a/drivers/gpu/drm/msm/dp/dp_utils.c b/drivers/gpu/drm/msm/dp/dp_utils.c
index 226b370ce8fe..72bae48a1fe0 100644
--- a/drivers/gpu/drm/msm/dp/dp_utils.c
+++ b/drivers/gpu/drm/msm/dp/dp_utils.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/types.h>
+#include <drm/drm_crtc.h>
 
 #include "dp_utils.h"
 
@@ -87,3 +88,9 @@ void msm_dp_utils_pack_sdp_header(const struct dp_sdp_header *sdp_header,
 		FIELD_PREP(HEADER_3_MASK, sdp_header->HB3) |
 		FIELD_PREP(PARITY_3_MASK, msm_dp_utils_calculate_parity(sdp_header->HB3));
 }
+
+bool msm_dp_utils_psr_needs_modeset(const struct drm_crtc_state *state)
+{
+	/* active_changed alone also describes a normal self-refresh exit. */
+	return state->mode_changed || state->connectors_changed;
+}
diff --git a/drivers/gpu/drm/msm/dp/dp_utils.h b/drivers/gpu/drm/msm/dp/dp_utils.h
index 2fdb89efc57c..5d86c978dffd 100644
--- a/drivers/gpu/drm/msm/dp/dp_utils.h
+++ b/drivers/gpu/drm/msm/dp/dp_utils.h
@@ -10,6 +10,8 @@
 #include <linux/bits.h>
 #include <drm/display/drm_dp_helper.h>
 
+struct drm_crtc_state;
+
 #define HEADER_BYTE_0_BIT	 0
 #define PARITY_BYTE_0_BIT	 8
 #define HEADER_BYTE_1_BIT	16
@@ -34,4 +36,6 @@ u8 msm_dp_utils_calculate_parity(u32 data);
 void msm_dp_utils_pack_sdp_header(const struct dp_sdp_header *sdp_header,
 				  u32 header_buff[2]);
 
+bool msm_dp_utils_psr_needs_modeset(const struct drm_crtc_state *state);
+
 #endif /* _DP_UTILS_H_ */

-- 
2.55.0