drm/nv50: fix duallink_possible calculation for DCB 4.0 cards

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

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c
index b3c7a87e47d9..9f30fb8eafe8 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.c
@@ -5536,12 +5536,6 @@ parse_dcb20_entry(struct drm_device *dev, struct dcb_table *dcb,
         entry->bus = (conn >> 16) & 0xf;
         entry->location = (conn >> 20) & 0x3;
         entry->or = (conn >> 24) & 0xf;
-        /*
-         * Normal entries consist of a single bit, but dual link has the
-         * next most significant bit set too
-         */
-        entry->duallink_possible =
-                        ((1 << (ffs(entry->or) - 1)) * 3 == entry->or);
 
         switch (entry->type) {
         case OUTPUT_ANALOG:
@@ -5625,6 +5619,16 @@ parse_dcb20_entry(struct drm_device *dev, struct dcb_table *dcb,
                 break;
         }
 
+        if (dcb->version < 0x40) {
+                /* Normal entries consist of a single bit, but dual link has
+                 * the next most significant bit set too
+                 */
+                entry->duallink_possible =
+                        ((1 << (ffs(entry->or) - 1)) * 3 == entry->or);
+        } else {
+                entry->duallink_possible = (entry->sorconf.link == 3);
+        }
+
         /* unsure what DCB version introduces this, 3.0? */
         if (conf & 0x100000)
                 entry->i2c_upper_default = true;