From 9859f71bc416da6771b8d66953d7cea68a998e00 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 17 Jul 2013 12:07:44 +0100 Subject: [PATCH] drm/i915: Fix dereferencing invalid connectors in is_crtc_connector_off() In commit e3de42b68478a8c95dd27520e9adead2af9477a5 Author: Imre Deak Date: Fri May 3 19:44:07 2013 +0200 drm/i915: force full modeset if the connector is in DPMS OFF mode a new function was added that walked over the set of connectors to see if any of the currently associated CRTC was switched off. This function walked an array of connectors, rather than the array of pointers to connectors contained in the drm_mode_set - i.e. it was dereferencing far past the end of the first connector. This only becomes an issue if we attempt to use a clone mode (i.e. more than one connector per CRTC) such that set->num_connectors > 1. Reported-by: Timo Aaltonen Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65927 Signed-off-by: Chris Wilson Cc: Imre Deak Cc: Egbert Eich Cc: Jesse Barnes Cc: Daniel Vetter Cc: stable@vger.kernel.org --- drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 9a10e71..6790600 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8658,15 +8658,20 @@ static void intel_set_config_restore_state(struct drm_device *dev, } static bool -is_crtc_connector_off(struct drm_crtc *crtc, struct drm_connector *connectors, - int num_connectors) +is_crtc_connector_off(struct drm_mode_set *set) { int i; - for (i = 0; i < num_connectors; i++) - if (connectors[i].encoder && - connectors[i].encoder->crtc == crtc && - connectors[i].dpms != DRM_MODE_DPMS_ON) + if (set->num_connectors == 0) + return false; + + if (WARN_ON(set->connectors == NULL)) + return false; + + for (i = 0; i < set->num_connectors; i++) + if (set->connectors[i]->encoder && + set->connectors[i]->encoder->crtc == set->crtc && + set->connectors[i]->dpms != DRM_MODE_DPMS_ON) return true; return false; @@ -8679,10 +8684,8 @@ intel_set_config_compute_mode_changes(struct drm_mode_set *set, /* We should be able to check here if the fb has the same properties * and then just flip_or_move it */ - if (set->connectors != NULL && - is_crtc_connector_off(set->crtc, *set->connectors, - set->num_connectors)) { - config->mode_changed = true; + if (is_crtc_connector_off(set)) { + config->mode_changed = true; } else if (set->crtc->fb != set->fb) { /* If we have no fb then treat it as a full mode set */ if (set->crtc->fb == NULL) { -- 1.8.3.2