From c0ed5bb682581e6ebb9df6f77df560f562148a57 Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude@redhat.com>
Date: Wed, 13 Dec 2023 19:43:57 -0500
Subject: drm/nouveau/kms/nv50-: Don't allow inheritance of headless iors
Git-commit: 7ba84cbf18c7a53107c64880d9c90f18fa68b481
Patch-mainline: v6.7-rc6
References: jsc#PED-3527 jsc#PED-5475 jsc#PED-6068 jsc#PED-6070 jsc#PED-6116 jsc#PED-6120 jsc#PED-5065 jsc#PED-5477 jsc#PED-5511 jsc#PED-6041 jsc#PED-6069 jsc#PED-6071
Turns out we made a silly mistake when coming up with OR inheritance on
nouveau. On pre-DCB 4.1, iors are statically routed to output paths via the
DCB. On later generations iors are only routed to an output path if they're
actually being used. Unfortunately, it appears with NVIF_OUTP_INHERIT_V0 we
make the mistake of assuming the later is true on all generations, which is
currently leading us to return bogus ior -> head assignments through nvif,
which causes WARN_ON().
So - fix this by verifying that we actually know that there's a head
assigned to an ior before allowing it to be inherited through nvif. This
-should- hopefully fix the WARN_ON on GT218 reported by Borislav.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Reported-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231214004359.1028109-1-lyude@redhat.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
index e4279f1772a1..377d0e0cef84 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uoutp.c
@@ -385,7 +385,7 @@ nvkm_uoutp_mthd_inherit(struct nvkm_outp *outp, void *argv, u32 argc)
/* Ensure an ior is hooked up to this outp already */
ior = outp->func->inherit(outp);
- if (!ior)
+ if (!ior || !ior->arm.head)
return -ENODEV;
/* With iors, there will be a separate output path for each type of connector - and all of
--
2.43.0