drm/nouveau/disp: power down unused DP links during init

When booted with multiple displays attached, the EFI GOP driver on (at
least) Ampere, can leave DP links powered up that aren't being used to
display anything.  This confuses our tracking of SOR routing, with the
likely result being a failed modeset and display engine hang.

Fix this by (ab?)using the DisableLT IED script to power-down the link,
restoring HW to a state the driver expects.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
index 55fbfe28c6dc1a50da06bc117a95cc91b303b4ac..9669472a2749ddc986fe9c6c1a0f9ba1a1bb2df3 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
@@ -440,7 +440,7 @@ nvkm_dp_train(struct nvkm_dp *dp, u32 dataKBps)
        return ret;
 }
 
-static void
+void
 nvkm_dp_disable(struct nvkm_outp *outp, struct nvkm_ior *ior)
 {
        struct nvkm_dp *dp = nvkm_dp(outp);

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.h b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.h
index 428b3f488f033af88d7627d2289cf388c524f72b..e484d0c3b0d42a9c8eb1d32607d852fcd5dddf9d 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.h
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.h
@@ -32,6 +32,7 @@ struct nvkm_dp {
 
 int nvkm_dp_new(struct nvkm_disp *, int index, struct dcb_output *,
                struct nvkm_outp **);
+void nvkm_dp_disable(struct nvkm_outp *, struct nvkm_ior *);
 
 /* DPCD Receiver Capabilities */
 #define DPCD_RC00_DPCD_REV                                              0x00000

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.c
index dffcac249211c3c02667d5e239ffade0916162b7..129982fef7ef66392e0622edf8c4df28d010ec33 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.c
@@ -22,6 +22,7 @@
  * Authors: Ben Skeggs
  */
 #include "outp.h"
+#include "dp.h"
 #include "ior.h"
 
 #include <subdev/bios.h>
@@ -257,6 +258,14 @@ nvkm_outp_init_route(struct nvkm_outp *outp)
        if (!ior->arm.head || ior->arm.proto != proto) {
                OUTP_DBG(outp, "no heads (%x %d %d)", ior->arm.head,
                         ior->arm.proto, proto);
+
+               /* The EFI GOP driver on Ampere can leave unused DP links routed,
+                * which we don't expect.  The DisableLT IED script *should* get
+                * us back to where we need to be.
+                */
+               if (ior->func->route.get && !ior->arm.head && outp->info.type == DCB_OUTPUT_DP)
+                       nvkm_dp_disable(outp, ior);
+
                return;
        }