From b7703726251191cd9f3ef3a80b2d9667901eec95 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 21 Jan 2015 08:45:22 +0100 Subject: [PATCH] drm/probe-helper: clamp unknown connector status in the poll work On some chipset we try to avoid possibly invasive output detection methods (like load detect which can cause flickering elsewhere) in the output poll work. Drivers could hence return unknown when a previous full ->detect call returned a different state. This change will generate a hotplug event, forcing userspace to do a full scan. This in turn updates the connector->status field so that we will _again_ get a state change when the hotplug work re-runs in 10 seconds. To avoid this ping-pong loop detect this situation and clamp the connector state to the old value. Patch is inspired by a patch from Knut Peterson. Knut's patch completely ignored connector state changes if either the old or new status was unknown, which seemed to be a bit too agressive to me. v2: Rebased onto the drm_probe_helper.c extraction. References: http://lists.freedesktop.org/archives/dri-devel/2012-August/025975.html Cc: Knut Petersen Cc: Alex Deucher Reviewed-by: Chris Wilson Acked-by: Alex Deucher Cc: Rob Clark Reviewed-by: Rob Clark Signed-off-by: Daniel Vetter --- Reading git-format-patch failed