If the crtc is active, we can simply flip a new fb onto it, provided the other mode setting reqs are met. Otherwise, we'll need to do a full mode set to re-enable the crtc. v2: check for crtc active and set mode_changed accordingly Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org> --- drivers/gpu/drm/i915/intel_display.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 150ace6..0701848 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8526,8 +8526,16 @@ intel_set_config_compute_mode_changes(struct drm_mode_set *set, if (set->crtc->fb != set->fb) { /* If we have no fb then treat it as a full mode set */ if (set->crtc->fb == NULL) { - DRM_DEBUG_KMS("crtc has no fb, full mode set\n"); - config->mode_changed = true; + struct intel_crtc *intel_crtc = + to_intel_crtc(set->crtc); + + if (intel_crtc->active) { + DRM_DEBUG_KMS("crtc has no fb, will flip\n"); + config->fb_changed = true; + } else { + DRM_DEBUG_KMS("inactive crtc, full mode set\n"); + config->mode_changed = true; + } } else if (set->fb == NULL) { config->mode_changed = true; } else if (set->fb->pixel_format != -- 1.7.9.5