[PATCH 1/4] drm/nouveau/kms/nv50-: Probe SOR caps for DP interlacing support

[Lyude Paul]

Right now, we make the mistake of allowing interlacing on all
connectors. Nvidia hardware does not always support interlacing with DP
though, so we need to make sure that we don't allow interlaced modes to
be set in such situations as otherwise we'll end up accidentally hanging
the display HW.

This fixes some hangs with Turing, which would be caused by attempting
to set an interlaced mode on hardware that doesn't support it. This
patch likely fixes other hardware hanging in the same way as well.

Signed-off-by: Lyude Paul <lyude at redhat.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c     | 21 ++++++++++++++-------
 drivers/gpu/drm/nouveau/nouveau_connector.c | 10 +++++++++-
 drivers/gpu/drm/nouveau/nouveau_encoder.h   |  3 +++
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index a3dc2ba19fb2..32a1c4221f1e 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1714,6 +1714,9 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 		struct nv50_disp *disp = nv50_disp(encoder->dev);
 		struct nvkm_i2c_aux *aux =
 			nvkm_i2c_aux_find(i2c, dcbe->i2c_index);
+		u32 caps = nvif_rd32(&disp->disp->object,
+				     0x00640144 + (nv_encoder->or * 8));
+
 		if (aux) {
 			if (disp->disp->object.oclass < GF110_DISP) {
 				/* HW has no support for address-only
@@ -1727,13 +1730,17 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 			nv_encoder->aux = aux;
 		}
 
-		if (nv_connector->type != DCB_CONNECTOR_eDP &&
-		    nv50_has_mst(drm)) {
-			ret = nv50_mstm_new(nv_encoder, &nv_connector->aux,
-					    16, nv_connector->base.base.id,
-					    &nv_encoder->dp.mstm);
-			if (ret)
-				return ret;
+		if (nv_connector->type != DCB_CONNECTOR_eDP) {
+			if (nv50_has_mst(drm)) {
+				ret = nv50_mstm_new(nv_encoder,
+						    &nv_connector->aux,
+						    16,
+						    connector->base.id,
+						    &nv_encoder->dp.mstm);
+				if (ret)
+					return ret;
+			}
+			nv_encoder->dp.caps.interlace = !!(caps & 0x04000000);
 		}
 	} else {
 		struct nvkm_i2c_bus *bus =
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 9a9a7f5003d3..97a84daf8eab 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -509,7 +509,11 @@ nouveau_connector_set_encoder(struct drm_connector *connector,
 	nv_connector->detected_encoder = nv_encoder;
 
 	if (drm->client.device.info.family >= NV_DEVICE_INFO_V0_TESLA) {
-		connector->interlace_allowed = true;
+		if (nv_encoder->dcb->type == DCB_OUTPUT_DP)
+			connector->interlace_allowed =
+				nv_encoder->dp.caps.interlace;
+		else
+			connector->interlace_allowed = true;
 		connector->doublescan_allowed = true;
 	} else
 	if (nv_encoder->dcb->type == DCB_OUTPUT_LVDS ||
@@ -1060,6 +1064,10 @@ nouveau_connector_mode_valid(struct drm_connector *connector,
 	case DCB_OUTPUT_TV:
 		return get_slave_funcs(encoder)->mode_valid(encoder, mode);
 	case DCB_OUTPUT_DP:
+		if (mode->flags & DRM_MODE_FLAG_INTERLACE &&
+		    !nv_encoder->dp.caps.interlace)
+			return MODE_NO_INTERLACE;
+
 		max_clock  = nv_encoder->dp.link_nr;
 		max_clock *= nv_encoder->dp.link_bw;
 		clock = clock * (connector->display_info.bpc * 3) / 10;
diff --git a/drivers/gpu/drm/nouveau/nouveau_encoder.h b/drivers/gpu/drm/nouveau/nouveau_encoder.h
index 3517f920bf89..2a8a7aec48c4 100644
--- a/drivers/gpu/drm/nouveau/nouveau_encoder.h
+++ b/drivers/gpu/drm/nouveau/nouveau_encoder.h
@@ -63,6 +63,9 @@ struct nouveau_encoder {
 			struct nv50_mstm *mstm;
 			int link_nr;
 			int link_bw;
+			struct {
+				bool interlace : 1;
+			} caps;
 		} dp;
 	};
 
-- 
2.24.1