From a76eb4297f90301fa9e4c888fb06749ef1be1c86 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Wed, 17 Aug 2022 15:38:42 -0400 Subject: drm/display/dp_mst: Add helpers for serializing SST <-> MST transitions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There's another kind of situation where we could potentially race with nonblocking modesets and MST, especially if we were to only use the locking provided by atomic modesetting: * Display 1 begins as enabled on DP-1 in SST mode * Display 1 switches to MST mode, exposes one sink in MST mode * Userspace does non-blocking modeset to disable the SST display * Userspace does non-blocking modeset to enable the MST display with a different CRTC, but the SST display hasn't been fully taken down yet * Execution order between the last two commits isn't guaranteed since they share no drm resources We can fix this however, by ensuring that we always pull in the atomic topology state whenever a connector capable of driving an MST display performs its atomic check - and then tracking CRTC commits happening on the SST connector in the MST topology state. So, let's add some simple helpers for doing that and hook them up in various drivers. v2: * Use intel_dp_mst_source_support() to check for MST support in i915, fixes CI failures Signed-off-by: Lyude Paul Cc: Wayne Lin Cc: Ville Syrjälä Cc: Fangzhi Zuo Cc: Jani Nikula Cc: Imre Deak Cc: Daniel Vetter Cc: Sean Paul Acked-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-14-lyude@redhat.com --- drivers/gpu/drm/nouveau/dispnv50/disp.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/gpu/drm/nouveau/dispnv50/disp.h') diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.h b/drivers/gpu/drm/nouveau/dispnv50/disp.h index 38dec11e7dda..9d66c9c726c3 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.h +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.h @@ -106,6 +106,8 @@ void nv50_dmac_destroy(struct nv50_dmac *); */ struct nouveau_encoder *nv50_real_outp(struct drm_encoder *encoder); +bool nv50_has_mst(struct nouveau_drm *drm); + u32 *evo_wait(struct nv50_dmac *, int nr); void evo_kick(u32 *, struct nv50_dmac *); -- cgit v1.2.3