drm/i915: fixup load-detect on enabled, but not active pipe

Somehow we have a fast-path that tries to avoid going through
the load-detect code when the encode already has a crtc associated.
But this fails horribly when the crtc is off. The load detect pipe
itself manages this case well (and also does not forget to restore the
dpms state), so just rip out this special case.

The issue seems to go back all the way to the commit that originally
introduced load-detection on the vga output:

commit e4a5d54f924ea5ce2913d9d0687d034004816465
Author: Ma Ling <ling.ma@intel.com>
Date:   Tue May 26 11:31:00 2009 +0800

    drm/i915: Add support for VGA load detection (pre-945).

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43020
Reported-by: Jean Delvare <khali@linux-fr.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 11 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 4d3d736a4f56..90b9793fd5da 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -430,8 +430,8 @@ intel_crt_detect(struct drm_connector *connector, bool force)
 {
         struct drm_device *dev = connector->dev;
         struct intel_crt *crt = intel_attached_crt(connector);
-        struct drm_crtc *crtc;
         enum drm_connector_status status;
+        struct intel_load_detect_pipe tmp;
 
         if (I915_HAS_HOTPLUG(dev)) {
                 if (intel_crt_detect_hotplug(connector)) {
@@ -450,23 +450,16 @@ intel_crt_detect(struct drm_connector *connector, bool force)
                 return connector->status;
 
         /* for pre-945g platforms use load detect */
-        crtc = crt->base.base.crtc;
-        if (crtc && crtc->enabled) {
-                status = intel_crt_load_detect(crt);
-        } else {
-                struct intel_load_detect_pipe tmp;
-
-                if (intel_get_load_detect_pipe(&crt->base, connector, NULL,
-                                               &tmp)) {
-                        if (intel_crt_detect_ddc(connector))
-                                status = connector_status_connected;
-                        else
-                                status = intel_crt_load_detect(crt);
-                        intel_release_load_detect_pipe(&crt->base, connector,
-                                                       &tmp);
-                } else
-                        status = connector_status_unknown;
-        }
+        if (intel_get_load_detect_pipe(&crt->base, connector, NULL,
+                                       &tmp)) {
+                if (intel_crt_detect_ddc(connector))
+                        status = connector_status_connected;
+                else
+                        status = intel_crt_load_detect(crt);
+                intel_release_load_detect_pipe(&crt->base, connector,
+                                               &tmp);
+        } else
+                status = connector_status_unknown;
 
         return status;
 }