[Nouveau] [PATCH 1/4] drm/nouveau: dispnv50: Don't create MSTMs for eDP connectors

[Lyude Paul]

On the ThinkPad P71, we have one eDP connector exposed along with 5 DP
connectors, resulting in a total of 11 TMDS encoders. Since the GPU on
this system is also capable of MST, we create an additional 4 fake MST
encoders for each DP port. Unfortunately, we also do this for the eDP
port as well, resulting in:

  1 eDP port: +1 TMDS encoder
              +4 DPMST encoders
  5 DP ports: +2 TMDS encoders
              +4 DPMST encoders
	      *5 ports
	      == 35 encoders

Which breaks things, since DRM has a hard coded limit of 32 encoders.
So, fix this by not creating MSTMs for any eDP connectors. This brings
us down to 31 encoders, although we can do better.

This fixes driver probing for nouveau on the ThinkPad P71.

Signed-off-by: Lyude Paul <lyude at redhat.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 307584107d77..b46be8a091e9 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1603,7 +1603,8 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe)
 			nv_encoder->aux = aux;
 		}
 
-		if ((data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len)) &&
+		if (nv_connector->type != DCB_CONNECTOR_eDP &&
+		    (data = nvbios_dp_table(bios, &ver, &hdr, &cnt, &len)) &&
 		    ver >= 0x40 && (nvbios_rd08(bios, data + 0x08) & 0x04)) {
 			ret = nv50_mstm_new(nv_encoder, &nv_connector->aux, 16,
 					    nv_connector->base.base.id,
-- 
2.21.0