drm/i915: Add a way to test the modeset done during gpu reset, v3.

Add force_reset_modeset_test as a parameter to force the modeset path during gpu reset.
This allows a IGT test to set the knob and trigger a hang to force the gpu reset,
even on platforms that wouldn't otherwise require it.

Changes since v1:
- Split out fix to separate commit.
Changes since v2:
- This commit is purely about force_reset_modeset_test now.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Testcase: drv_hangman.reset-with-forced-modeset
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470428910-12125-3-git-send-email-ville.syrjala@linux.intel.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index b6e404c..768ad89 100644 (file)
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -45,6 +45,7 @@ struct i915_params i915 __read_mostly = {
        .fastboot = 0,
        .prefault_disable = 0,
        .load_detect_test = 0,
+       .force_reset_modeset_test = 0,
        .reset = true,
        .invert_brightness = 0,
        .disable_display = 0,
@@ -161,6 +162,11 @@ MODULE_PARM_DESC(load_detect_test,
        "Force-enable the VGA load detect code for testing (default:false). "
        "For developers only.");
 
+module_param_named_unsafe(force_reset_modeset_test, i915.force_reset_modeset_test, bool, 0600);
+MODULE_PARM_DESC(force_reset_modeset_test,
+       "Force a modeset during gpu reset for testing (default:false). "
+       "For developers only.");
+
 module_param_named_unsafe(invert_brightness, i915.invert_brightness, int, 0600);
 MODULE_PARM_DESC(invert_brightness,
        "Invert backlight brightness "

diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 0ad020b..3a0dd78 100644 (file)
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -57,6 +57,7 @@ struct i915_params {
        bool fastboot;
        bool prefault_disable;
        bool load_detect_test;
+       bool force_reset_modeset_test;
        bool reset;
        bool disable_display;
        bool verbose_state_checks;

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a951395..8fa200b 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3161,7 +3161,8 @@ void intel_prepare_reset(struct drm_i915_private *dev_priv)
        }
 
        /* reset doesn't touch the display, but flips might get nuked anyway, */
-       if (INTEL_GEN(dev_priv) >= 5 || IS_G4X(dev_priv))
+       if (!i915.force_reset_modeset_test &&
+           (INTEL_GEN(dev_priv) >= 5 || IS_G4X(dev_priv)))
                return;
 
        /*
@@ -3212,16 +3213,22 @@ void intel_finish_reset(struct drm_i915_private *dev_priv)
 
        /* reset doesn't touch the display */
        if (INTEL_GEN(dev_priv) >= 5 || IS_G4X(dev_priv)) {
-               /*
-                * Flips in the rings have been nuked by the reset,
-                * so update the base address of all primary
-                * planes to the the last fb to make sure we're
-                * showing the correct fb after a reset.
-                *
-                * FIXME: Atomic will make this obsolete since we won't schedule
-                * CS-based flips (which might get lost in gpu resets) any more.
-                */
-               intel_update_primary_planes(dev);
+               if (!state) {
+                       /*
+                        * Flips in the rings have been nuked by the reset,
+                        * so update the base address of all primary
+                        * planes to the the last fb to make sure we're
+                        * showing the correct fb after a reset.
+                        *
+                        * FIXME: Atomic will make this obsolete since we won't schedule
+                        * CS-based flips (which might get lost in gpu resets) any more.
+                        */
+                       intel_update_primary_planes(dev);
+               } else {
+                       ret = __intel_display_resume(dev, state);
+                       if (ret)
+                               DRM_ERROR("Restoring old state failed with %i\n", ret);
+               }
        } else {
                /*
                 * The display has been reset as well,