Attachment 62862 Details for Bug 50501 – only try the edid detction, not load detect as a fallback

[patch] only try the edid detction, not load detect as a fallback

0001-drm-i915-crt-Do-not-rely-upon-the-HPD-presence-pin.patch (text/plain), 2.54 KB, created by Daniel Vetter on 2012-06-10 10:09:55 UTC

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Creator: Daniel Vetter

Created: 2012-06-10 10:09:55 UTC

Size: 2.54 KB

patch

obsolete

>From cc95fcd472a70f6dacacd3a56b126596b40976ba Mon Sep 17 00:00:00 2001
>From: Chris Wilson <chris@chris-wilson.co.uk>
>Date: Thu, 31 May 2012 13:08:53 +0100
>Subject: [PATCH] drm/i915/crt: Do not rely upon the HPD presence pin
>
>VGA hotplug detection "works" by measuring the resistance across
>certain pins. A lot of kvm switches fumble this and wire up cheap
>resistors with the wrong value or don't bother at all.
>
>To accomodate these, also try to detect a connected monitor by trying
>to grab the edid. Contrary to !HAS_HOTPLUG platforms we don't bother
>with an actual load-detection cycle when the output is life - that
>would be actual work to implement because things moved around. This is
>the big difference to Chris Wilson's original approach:
>
>commit 9e612a008fa7fe493a473454def56aa321479495
>Author: Chris Wilson <chris@chris-wilson.co.uk>
>Date:   Thu May 31 13:08:53 2012 +0100
>
>    drm/i915/crt: Do not rely upon the HPD presence pin
>
>This blew up on Linus' machine because it errornously detected a vga
>screen (without and edid and hence only the default modes), leading to
>it's prompt removal:
>
>commit 8f53369b753f5f4c7684c2eb0b592152abb1dd00
>Author: Linus Torvalds <torvalds@linux-foundation.org>
>Date:   Fri Jun 8 14:53:06 2012 -0700
>
>    Revert "drm/i915/crt: Do not rely upon the HPD presence pin"
>
>Reported-by: Matthieu LAVIE <boiteamadmax@hotmail.com>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50501
>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>---
> drivers/gpu/drm/i915/intel_crt.c |   11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
>index 75a70c4..7155181 100644
>--- a/drivers/gpu/drm/i915/intel_crt.c
>+++ b/drivers/gpu/drm/i915/intel_crt.c
>@@ -453,18 +453,23 @@ intel_crt_detect(struct drm_connector *connector, bool force)
> 	struct intel_load_detect_pipe tmp;
> 
> 	if (I915_HAS_HOTPLUG(dev)) {
>+		/* We can not rely on the HPD pin always being correctly wired
>+		 * up, for example many KVM do not pass it through, and so
>+		 * only trust an assertion that the monitor is connected.
>+		 */
> 		if (intel_crt_detect_hotplug(connector)) {
> 			DRM_DEBUG_KMS("CRT detected via hotplug\n");
> 			return connector_status_connected;
>-		} else {
>+		} else
> 			DRM_DEBUG_KMS("CRT not detected via hotplug\n");
>-			return connector_status_disconnected;
>-		}
> 	}
> 
> 	if (intel_crt_detect_ddc(connector))
> 		return connector_status_connected;
> 
>+	if (I915_HAS_HOTPLUG(dev))
>+		return connector_status_disconnected;
>+
> 	if (!force)
> 		return connector->status;
> 
>-- 
>1.7.10
>

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Attachments on bug 50501: 62285 | 62286 | 62287 | 62292 | 62317 | 62318 | 62319 | 62333 | 62334 | 62862 | 62868 | 62869

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