drm/nouveau/kms: disallow dual-link harder if hdmi connection detected

The fallthrough cases (pre-Fermi) would accidentally allow dual-link pixel
clocks even where they shouldn't be.  This leads to a high resolution HDMI
displays, connected via a DVI->HDMI adapter, to fail on the original NV50.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 4116ee62adaf..caa8c7595889 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -978,11 +978,13 @@ get_tmds_link_bandwidth(struct drm_connector *connector)
         struct nouveau_drm *drm = nouveau_drm(connector->dev);
         struct dcb_output *dcb = nv_connector->detected_encoder->dcb;
         struct drm_display_info *info = NULL;
-        const unsigned duallink_scale =
+        unsigned duallink_scale =
                 nouveau_duallink && nv_encoder->dcb->duallink_possible ? 2 : 1;
 
-        if (drm_detect_hdmi_monitor(nv_connector->edid))
+        if (drm_detect_hdmi_monitor(nv_connector->edid)) {
                 info = &nv_connector->base.display_info;
+                duallink_scale = 1;
+        }
 
         if (info) {
                 if (nouveau_hdmimhz > 0)
@@ -1003,6 +1005,7 @@ get_tmds_link_bandwidth(struct drm_connector *connector)
                 if (drm->client.device.info.family >= NV_DEVICE_INFO_V0_FERMI)
                         return 225000;
         }
+
         if (dcb->location != DCB_LOC_ON_CHIP ||
             drm->client.device.info.chipset >= 0x46)
                 return 165000 * duallink_scale;