[PATCH 4/5] drm/i915: Add FBC debugfs disabling

[jeff.mcgee@intel.com]

From: Jeff McGee <jeff.mcgee@intel.com>

i915_fbc_disable:
'0' - FBC enabled normally per device and settings.
'1' - FBC explicitly disabled.

Signed-off-by: Jeff McGee <jeff.mcgee@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 50 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_drv.h     |  3 +++
 drivers/gpu/drm/i915/intel_pm.c     |  5 ++++
 3 files changed, 58 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 949c6a4..92f6213 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1386,6 +1386,9 @@ static int i915_fbc_status(struct seq_file *m, void *unused)
 		case FBC_CHIP_DEFAULT:
 			seq_puts(m, "disabled per chip default");
 			break;
+		case FBC_DEBUG_FS:
+			seq_puts(m, "disabled per debugfs");
+			break;
 		default:
 			seq_puts(m, "unknown reason");
 		}
@@ -1394,6 +1397,52 @@ static int i915_fbc_status(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static int i915_fbc_disable_get(void *data, u64 *val)
+{
+	struct drm_device *dev = data;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+
+	if (!HAS_FBC(dev))
+		return -ENODEV;
+
+	*val = dev_priv->fbc.disable;
+
+	return 0;
+}
+
+static int i915_fbc_disable_set(void *data, u64 val)
+{
+	struct drm_device *dev = data;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc;
+
+	if (!HAS_FBC(dev))
+		return -ENODEV;
+
+	if (dev_priv->fbc.disable == (bool)val)
+		return 0;
+
+	drm_modeset_lock_all(dev);
+
+	DRM_DEBUG_DRIVER("Setting FBC disable %s\n",
+			 val ? "true" : "false");
+
+	dev_priv->fbc.disable = (bool)val;
+
+	/* Reset enabled crtc to force FBC state update */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+		if (crtc->enabled)
+			intel_crtc_restore_mode(crtc);
+
+	drm_modeset_unlock_all(dev);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(i915_fbc_disable_fops,
+			i915_fbc_disable_get, i915_fbc_disable_set,
+			"%llu\n");
+
 static int i915_ips_status(struct seq_file *m, void *unused)
 {
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
@@ -3703,6 +3752,7 @@ static const struct i915_debugfs_files {
 	{"i915_rps_manual", &i915_rps_manual_fops},
 	{"i915_rc6_disable", &i915_rc6_disable_fops},
 	{"i915_ips_disable", &i915_ips_disable_fops},
+	{"i915_fbc_disable", &i915_fbc_disable_fops},
 	{"i915_cache_sharing", &i915_cache_sharing_fops},
 	{"i915_ring_stop", &i915_ring_stop_fops},
 	{"i915_ring_missed_irq", &i915_ring_missed_irq_fops},
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 93e1547..18b2849 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -763,7 +763,10 @@ struct i915_fbc {
 		FBC_MULTIPLE_PIPES, /* more than one pipe active */
 		FBC_MODULE_PARAM,
 		FBC_CHIP_DEFAULT, /* disabled by default on this chip */
+		FBC_DEBUG_FS, /* user requests disabling through debugfs */
 	} no_fbc_reason;
+
+	bool disable;
 };
 
 struct i915_psr {
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6478116..a8605fc 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -519,6 +519,11 @@ void intel_update_fbc(struct drm_device *dev)
 			DRM_DEBUG_KMS("fbc disabled per module param\n");
 		goto out_disable;
 	}
+	if (dev_priv->fbc.disable) {
+		if (set_no_fbc_reason(dev_priv, FBC_DEBUG_FS))
+			DRM_DEBUG_KMS("fbc disabled per debugfs\n");
+		goto out_disable;
+	}
 	if ((adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE) ||
 	    (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)) {
 		if (set_no_fbc_reason(dev_priv, FBC_UNSUPPORTED_MODE))
-- 
1.8.5.2