drm/i915: Add module param to test the load detect code

This is useful for writing igts to make sure we don't break this,
without being forced to own a one of these dinosaurs.

Suggested-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

3 files changed, 12 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a4db7a7db444..6ccdf954b1ca 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2462,6 +2462,7 @@ struct i915_params {
         bool enable_hangcheck;
         bool fastboot;
         bool prefault_disable;
+        bool load_detect_test;
         bool reset;
         bool disable_display;
         bool disable_vtd_wa;
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index f3b8b62cb74d..bb64415a1c3e 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -43,6 +43,7 @@ struct i915_params i915 __read_mostly = {
         .enable_ips = 1,
         .fastboot = 0,
         .prefault_disable = 0,
+        .load_detect_test = 0,
         .reset = true,
         .invert_brightness = 0,
         .disable_display = 0,
@@ -139,11 +140,16 @@ module_param_named(fastboot, i915.fastboot, bool, 0600);
 MODULE_PARM_DESC(fastboot,
         "Try to skip unnecessary mode sets at boot time (default: false)");
 
-module_param_named(prefault_disable, i915.prefault_disable, bool, 0600);
+module_param_named_unsafe(prefault_disable, i915.prefault_disable, bool, 0600);
 MODULE_PARM_DESC(prefault_disable,
         "Disable page prefaulting for pread/pwrite/reloc (default:false). "
         "For developers only.");
 
+module_param_named_unsafe(load_detect_test, i915.load_detect_test, bool, 0600);
+MODULE_PARM_DESC(load_detect_test,
+        "Force-enable the VGA load detect code for testing (default:false). "
+        "For developers only.");
+
 module_param_named(invert_brightness, i915.invert_brightness, int, 0600);
 MODULE_PARM_DESC(invert_brightness,
         "Invert backlight brightness "
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 573aaff3389a..6095a998bdac 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -690,7 +690,7 @@ intel_crt_detect(struct drm_connector *connector, bool force)
          * broken monitor (without edid) to work behind a broken kvm (that fails
          * to have the right resistors for HP detection) needs to fix this up.
          * For now just bail out. */
-        if (I915_HAS_HOTPLUG(dev)) {
+        if (I915_HAS_HOTPLUG(dev) && !i915.load_detect_test) {
                 status = connector_status_disconnected;
                 goto out;
         }
@@ -706,8 +706,10 @@ intel_crt_detect(struct drm_connector *connector, bool force)
         if (intel_get_load_detect_pipe(connector, NULL, &tmp, &ctx)) {
                 if (intel_crt_detect_ddc(connector))
                         status = connector_status_connected;
-                else
+                else if (INTEL_INFO(dev)->gen < 4)
                         status = intel_crt_load_detect(crt);
+                else
+                        status = connector_status_unknown;
                 intel_release_load_detect_pipe(connector, &tmp, &ctx);
         } else
                 status = connector_status_unknown;