drm/i915/ibx, cpt: Don't attempt to register eDP if LVDS was detected

Atm on IBX/CPT we attempt to detect if eDP is present even if LVDS was
already detected and an encoder for it was registered. This involves
trying to read out the eDP DPCD, which in turn needs the same power
sequencer that LVDS uses. Poking at the VDD line at an unexpected time
may or may not interfere with the LVDS panel, but it's probably safer to
prevent this. Registering both an LVDS and an eDP connector would also
present a similar problem accessing the shared PPS at any point later in
an unexpected way.

We also need this to be able fix PPS initialization before its first use
in the next patch. For that we want to be sure that PPS is not in use
by LVDS.

v2:
- Split out the PPS init fix to a separate patch. (Chris)
- Add comment about eDP init depending on LVDS init. (Chris)
- Make the use of the intel_encoder ptr less error prone.
v3:
- Use IBX/CPT reference instead of the incorrect ILK, add a WARN about
  this. (Ville)
v4:
- Use a helper to get the lvds encoder instead of opencoding the same.
  (Ville)

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v3)
Link: http://patchwork.freedesktop.org/patch/msgid/1466499109-20240-2-git-send-email-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8c6f4e2a2cb8638dc5b3390531118a47cc97ed2d..b6bb43875a03c6b726844ae994518566c7546b17 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -14708,6 +14708,11 @@ static void intel_setup_outputs(struct drm_device *dev)
        struct intel_encoder *encoder;
        bool dpd_is_edp = false;
 
+       /*
+        * intel_edp_init_connector() depends on this completing first, to
+        * prevent the registeration of both eDP and LVDS and the incorrect
+        * sharing of the PPS.
+        */
        intel_lvds_init(dev);
 
        if (intel_crt_present(dev))

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3cdea4d7a917ce520dae03a416289b2a051e9068..9493c8f765383e0b53bfad9ee2e7b5a960b417e9 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5313,6 +5313,19 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
        if (!is_edp(intel_dp))
                return true;
 
+       /*
+        * On IBX/CPT we may get here with LVDS already registered. Since the
+        * driver uses the only internal power sequencer available for both
+        * eDP and LVDS bail out early in this case to prevent interfering
+        * with an already powered-on LVDS power sequencer.
+        */
+       if (intel_get_lvds_encoder(dev)) {
+               WARN_ON(!(HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv)));
+               DRM_INFO("LVDS was detected, not registering eDP\n");
+
+               return false;
+       }
+
        pps_lock(intel_dp);
        intel_edp_panel_vdd_sanitize(intel_dp);
        pps_unlock(intel_dp);

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 06fa25db3d32f4665f8ded28be8b3f4e1edb6033..21ba3df05241380068b74d3c3ec1cd214559facb 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1460,6 +1460,7 @@ void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
 
 /* intel_lvds.c */
 void intel_lvds_init(struct drm_device *dev);
+struct intel_encoder *intel_get_lvds_encoder(struct drm_device *dev);
 bool intel_is_dual_link_lvds(struct drm_device *dev);
 
 

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index e06b9036bebc6d3bddf41fd82aad9297e31c6d5e..72096fd28023c5d061a9ddafe1f9b27c6ce4a3a8 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -809,20 +809,22 @@ static const struct dmi_system_id intel_dual_link_lvds[] = {
        { }     /* terminating entry */
 };
 
-bool intel_is_dual_link_lvds(struct drm_device *dev)
+struct intel_encoder *intel_get_lvds_encoder(struct drm_device *dev)
 {
-       struct intel_encoder *encoder;
-       struct intel_lvds_encoder *lvds_encoder;
+       struct intel_encoder *intel_encoder;
 
-       for_each_intel_encoder(dev, encoder) {
-               if (encoder->type == INTEL_OUTPUT_LVDS) {
-                       lvds_encoder = to_lvds_encoder(&encoder->base);
+       for_each_intel_encoder(dev, intel_encoder)
+               if (intel_encoder->type == INTEL_OUTPUT_LVDS)
+                       return intel_encoder;
 
-                       return lvds_encoder->is_dual_link;
-               }
-       }
+       return NULL;
+}
 
-       return false;
+bool intel_is_dual_link_lvds(struct drm_device *dev)
+{
+       struct intel_encoder *encoder = intel_get_lvds_encoder(dev);
+
+       return encoder && to_lvds_encoder(&encoder->base)->is_dual_link;
 }
 
 static bool compute_is_dual_link_lvds(struct intel_lvds_encoder *lvds_encoder)