linux-kernel - [PATCH] Revert "drm: Stop resetting connector state to unknown"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 15 Dec 2015 13:07:51 -0500
From:	Lyude <cpaul@...hat.com>
To:	David Airlie <airlied@...ux.ie>,
	dri-devel@...ts.freedesktop.org (open list:DRM DRIVERS),
	linux-kernel@...r.kernel.org (open list),
	Daniel Vetter <daniel.vetter@...ll.ch>
Cc:	Rui Matos <tiagomatos@...il.com>,
	Julien Wajsberg <felash@...il.com>, kuddel.mail@....de,
	Lennart Poettering <mzxreary@...inter.de>,
	Rob Clark <robdclark@...il.com>,
	Benjamin Tissoires <benjamin.tissoires@...hat.com>,
	Lyude <cpaul@...hat.com>
Subject: [PATCH] Revert "drm: Stop resetting connector state to unknown"

This reverts commit 5677d67ae394 ("drm: Stop resetting connector state to
unknown")

Unfortunately, not resetting the connector status to unknown actually
breaks reprobing on suspend/resume in i915, which is important to have
working since it means a user docking their laptop in suspend won't have
their monitors work after resume. This commit was originally pushed to fix
a bug with systemd[1], however said bug has already been fixed in
userspace.

Since "unknown" is technically a valid option to return to userspace for a
connector's status, I would think that this sort of behavior should
probably be expected from userspace. Some good examples of this are the
radeon driver reporting "unknown" for connectors that have done something
wonky during a hotplug event (e.g. part of the initialization of the
connector failed), and the omapdrm driver returns "unknown" for certain
connector types by default.

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=100641

Signed-off-by: Lyude <cpaul@...hat.com>
---
 drivers/gpu/drm/drm_crtc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 24c5434..474e636 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5312,11 +5312,12 @@ void drm_mode_config_reset(struct drm_device *dev)
 		if (encoder->funcs->reset)
 			encoder->funcs->reset(encoder);

-	mutex_lock(&dev->mode_config.mutex);
-	drm_for_each_connector(connector, dev)
+	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+		connector->status = connector_status_unknown;
+
 		if (connector->funcs->reset)
 			connector->funcs->reset(connector);
-	mutex_unlock(&dev->mode_config.mutex);
+	}
 }
 EXPORT_SYMBOL(drm_mode_config_reset);

-- 
2.5.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/