From 2a7bcc5e1f9c99072e669203b09ff0d0940cf76a Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 29 Aug 2012 20:00:33 +0200 Subject: [PATCH] drm/i915: don't disable disconnected outputs This piece of neat lore has been ported painstakingly and bug-for-bug compatible from the old crtc helper code. Imo it's utter nonsense. If you disconnected a cable and before you reconnect it, userspace (or the kernel) does an set_crtc call, this will result in that connector getting disabled. Which will result in a nice black screen when plugging in the cable again. There's absolutely no reason the kernel does such policy enforcements - if userspace tries to set up a mode on something disconnected we might fail loudly (since the dp link training fails), but silently adjusting the output configuration behind userspace's back is a recipe for disaster. Specifically I think that this could explain some of our MI_WAIT hangs around suspend, where userspace issues a scanline wait on a disable pipe. This mechanisims here could explain how that pipe got disabled without userspace noticing. Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 5958b3b..3b6e4b0 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7817,10 +7817,6 @@ intel_modeset_stage_output_state(struct drm_device *dev, DRM_DEBUG_KMS("encoder changed, full mode switch\n"); config->mode_changed = true; } - - /* Disable all disconnected encoders. */ - if (connector->base.status == connector_status_disconnected) - connector->new_encoder = NULL; } /* connector->new_encoder is now updated for all connectors. */ -- 1.7.10.4