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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ben Skeggs <bskeggs@redhat.com>, Lyude Paul <lyude@redhat.com>,
	Sasha Levin <sashal@kernel.org>,
	dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org
Subject: [PATCH AUTOSEL 5.4 08/10] drm/nouveau/disp: power down unused DP links during init
Date: Mon, 23 Aug 2021 20:54:55 -0400	[thread overview]
Message-ID: <20210824005458.631377-8-sashal@kernel.org> (raw)
In-Reply-To: <20210824005458.631377-1-sashal@kernel.org>

From: Ben Skeggs <bskeggs@redhat.com>

[ Upstream commit 6eaa1f3c59a707332e921e32782ffcad49915c5e ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c   | 2 +-
 drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.h   | 1 +
 drivers/gpu/drm/nouveau/nvkm/engine/disp/outp.c | 9 +++++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
index 818d21bd28d3..1d2837c5a8f2 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/dp.c
@@ -419,7 +419,7 @@ 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 428b3f488f03..e484d0c3b0d4 100644
--- 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 c62030c96fba..4b1c72fd8f03 100644
--- 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>
@@ -216,6 +217,14 @@ 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;
 	}
 
-- 
2.30.2


  parent reply	other threads:[~2021-08-24  0:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24  0:54 [PATCH AUTOSEL 5.4 01/10] opp: remove WARN when no valid OPPs remain Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 02/10] virtio: Improve vq->broken access to avoid any compiler optimization Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 03/10] virtio_pci: Support surprise removal of virtio pci device Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 04/10] vringh: Use wiov->used to check for read/write desc order Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 05/10] qed: qed ll2 race condition fixes Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 06/10] qed: Fix null-pointer dereference in qed_rdma_create_qp() Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 07/10] drm: Copy drm_wait_vblank to user before returning Sasha Levin
2021-08-24  0:54 ` Sasha Levin [this message]
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 09/10] drm/nouveau: block a bunch of classes from userspace Sasha Levin
2021-08-24  0:54 ` [PATCH AUTOSEL 5.4 10/10] net/rds: dma_map_sg is entitled to merge entries Sasha Levin

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