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authorDaniel Vetter <daniel.vetter@ffwll.ch>2015-08-03 18:24:11 +0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2015-08-04 12:10:41 +0300
commit6ea76f3cade4734e73e3da842005820558b8b828 (patch)
treee6b5c9c487f5134e63b981308079e9614b7bdd6a /drivers/gpu/drm
parent42639ba554655c280ae6cb72df0522b1201f2961 (diff)
downloadlinux-6ea76f3cade4734e73e3da842005820558b8b828.tar.xz
drm/atomic-helpers: Make encoder picking more robust
We've had a few issues with atomic where subtle bugs in the encoder picking logic lead to accidental self-stealing of the encoder, resulting in a NULL connector_state->crtc in update_connector_routing and subsequent. Linus applied some duct-tape for an mst regression in commit 27667f4744fc5a0f3e50910e78740bac5670d18b Author: Linus Torvalds <torvalds@linux-foundation.org> Date: Wed Jul 29 22:18:16 2015 -0700 i915: temporary fix for DP MST docking station NULL pointer dereference But that was incomplete (the code will still oops when debuggin is enabled) and mangled the state even further. So instead WARN and bail out as the more future-proof option. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/drm_atomic_helper.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8694ca9beee3..9dcc7280e572 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -234,13 +234,14 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx)
}
}
+ if (WARN_ON(!connector_state->crtc))
+ return -EINVAL;
+
connector_state->best_encoder = new_encoder;
- if (connector_state->crtc) {
- idx = drm_crtc_index(connector_state->crtc);
+ idx = drm_crtc_index(connector_state->crtc);
- crtc_state = state->crtc_states[idx];
- crtc_state->mode_changed = true;
- }
+ crtc_state = state->crtc_states[idx];
+ crtc_state->mode_changed = true;
DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] using [ENCODER:%d:%s] on [CRTC:%d]\n",
connector->base.id,