Attachment 71704 Details for Bug 58396 – don't auto-disable disconnected outputs

[patch] don't auto-disable disconnected outputs

0001-drm-i915-don-t-disable-disconnected-outputs.patch (text/plain), 1.83 KB, created by Daniel Vetter on 2012-12-17 23:46:42 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Daniel Vetter

Created: 2012-12-17 23:46:42 UTC

Size: 1.83 KB

patch

obsolete

>From 2a7bcc5e1f9c99072e669203b09ff0d0940cf76a Mon Sep 17 00:00:00 2001
>From: Daniel Vetter <daniel.vetter@ffwll.ch>
>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 <daniel.vetter@ffwll.ch>
>---
> 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
>

Actions: View | Splinter Review

Attachments on bug 58396: 71635 | 71636 | 71637 | 71656 | 71659 | 71675 | 71676 | 71689 | 71697 | 71704 | 71709

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.