drm/nouveau/disp: limit dp capabilities as per dcb
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/dport.c b/drivers/gpu/drm/nouveau/core/engine/disp/dport.c
index 1bd4c63..2aedb4e 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/dport.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/dport.c
@@ -312,6 +312,14 @@
ERR("failed to read DPCD\n");
}
+ /* bring capabilities within encoder limits */
+ if ((dp->dpcd[2] & 0x1f) > dp->outp->dpconf.link_nr) {
+ dp->dpcd[2] &= ~0x1f;
+ dp->dpcd[2] |= dp->outp->dpconf.link_nr;
+ }
+ if (dp->dpcd[1] > dp->outp->dpconf.link_bw)
+ dp->dpcd[1] = dp->outp->dpconf.link_bw;
+
/* adjust required bandwidth for 8B/10B coding overhead */
datarate = (datarate / 8) * 10;