drm/i915: disable cloning on sdvo

After the recent pile of disable-cloning patches, e.g.

commit e3b86d6941c7e5f90be05d986fce1fcb40c68d6b
Author: Egbert Eich <eich@suse.de>
Date:   Sat Oct 13 14:30:15 2012 +0200

    DRM/i915: Don't clone SDVO LVDS with analog

and a bug report from Chris Wilson indicating that cloning doesn't
even work for DVI-SDVO and native VGA, let's just disable cloning on
sdvo encoders completely.

v2: Update the comment in the code as discussed with Paulo Zanoni.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29259
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 10 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index c600fb06e25e..a6ac0b416964 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2201,7 +2201,6 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
                 connector->connector_type = DRM_MODE_CONNECTOR_HDMIA;
                 intel_sdvo->is_hdmi = true;
         }
-        intel_sdvo->base.cloneable = true;
 
         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
         if (intel_sdvo->is_hdmi)
@@ -2232,7 +2231,6 @@ intel_sdvo_tv_init(struct intel_sdvo *intel_sdvo, int type)
 
         intel_sdvo->is_tv = true;
         intel_sdvo->base.needs_tv_clock = true;
-        intel_sdvo->base.cloneable = false;
 
         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
 
@@ -2275,8 +2273,6 @@ intel_sdvo_analog_init(struct intel_sdvo *intel_sdvo, int device)
                 intel_sdvo_connector->output_flag = SDVO_OUTPUT_RGB1;
         }
 
-        intel_sdvo->base.cloneable = true;
-
         intel_sdvo_connector_init(intel_sdvo_connector,
                                   intel_sdvo);
         return true;
@@ -2307,9 +2303,6 @@ intel_sdvo_lvds_init(struct intel_sdvo *intel_sdvo, int device)
                 intel_sdvo_connector->output_flag = SDVO_OUTPUT_LVDS1;
         }
 
-        /* SDVO LVDS is not cloneable because the input mode gets adjusted by the encoder */
-        intel_sdvo->base.cloneable = false;
-
         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
         if (!intel_sdvo_create_enhance_property(intel_sdvo, intel_sdvo_connector))
                 goto err;
@@ -2721,6 +2714,16 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
                 goto err_output;
         }
 
+        /*
+         * Cloning SDVO with anything is often impossible, since the SDVO
+         * encoder can request a special input timing mode. And even if that's
+         * not the case we have evidence that cloning a plain unscaled mode with
+         * VGA doesn't really work. Furthermore the cloning flags are way too
+         * simplistic anyway to express such constraints, so just give up on
+         * cloning for SDVO encoders.
+         */
+        intel_sdvo->base.cloneable = false;
+
         /* Only enable the hotplug irq if we need it, to work around noisy
          * hotplug lines.
          */