Revert "drm/i915/crt: Do not rely upon the HPD presence pin"

This reverts commit 9e612a008fa7fe493a473454def56aa321479495.

It incorrectly finds VGA connectors where none are attached, apparently
not noticing that nothing replied to the EDID queries, and happily using
the default EDID modes that have nothing to do with actual hardware.

That in turn then causes X to fall down to the lowest common
denominator, which is usually the default 1024x768 mode that is in the
default EDID and pretty much anything supports).

I'd suggest that if not relying on the HDP pin, the code should at least
check whether it gets valid EDID data back, rather than just assume
there's something on the VGA connector.

Cc: Dave Airlie <airlied@linux.ie>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 844e93e1e395..75a70c46ef1b 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -453,15 +453,13 @@ 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))