[Intel-gfx] [PATCH 1/2] drm/i915/display/dsc: Add Per connector debugfs node for DSC BPP enable

[venkata.sai.patnana at intel.com]

From: Anusha Srivatsa <anusha.srivatsa at intel.com>

DSC can be supported per DP connector. This patch creates
a per connector debugfs node to expose the Input and
Compressed BPP.

The same node can be used from userspace to force
DSC to a certain BPP.

force_dsc_bpp is written through this debugfs
node to force DSC BPP to all accepted values

Cc: Vandita Kulkarni <vandita.kulkarni at intel.com>
Cc: Navare Manasi D <manasi.d.navare at intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
Signed-off-by: Patnana Venkata Sai <venkata.sai.patnana at intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  | 103 +++++++++++++++++-
 .../drm/i915/display/intel_display_types.h    |   1 +
 2 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index af9e58619667d..6dc223227eeaa 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -2389,6 +2389,100 @@ static const struct file_operations i915_dsc_fec_support_fops = {
 	.write = i915_dsc_fec_support_write
 };
 
+static int i915_dsc_bpp_support_show(struct seq_file *m, void *data)
+{
+	struct drm_connector *connector = m->private;
+	struct drm_device *dev = connector->dev;
+	struct drm_crtc *crtc;
+	struct intel_dp *intel_dp;
+	struct drm_modeset_acquire_ctx ctx;
+	struct intel_crtc_state *crtc_state = NULL;
+	int ret = 0;
+	bool try_again = false;
+
+	drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
+
+	do {
+		try_again = false;
+		ret = drm_modeset_lock(&dev->mode_config.connection_mutex,
+				       &ctx);
+		if (ret) {
+			ret = -EINTR;
+			break;
+		}
+		crtc = connector->state->crtc;
+		if (connector->status != connector_status_connected || !crtc) {
+			ret = -ENODEV;
+			break;
+		}
+		ret = drm_modeset_lock(&crtc->mutex, &ctx);
+		if (ret == -EDEADLK) {
+			ret = drm_modeset_backoff(&ctx);
+			if (!ret) {
+				try_again = true;
+				continue;
+			}
+			break;
+		} else if (ret) {
+			break;
+		}
+		intel_dp = intel_attached_dp(to_intel_connector(connector));
+		crtc_state = to_intel_crtc_state(crtc->state);
+		seq_printf(m, "Input_BPP: %d\n", crtc_state->pipe_bpp);
+		seq_printf(m, "Compressed_BPP: %d\n",
+				crtc_state->dsc.compressed_bpp);
+	} while (try_again);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	return ret;
+}
+
+static ssize_t i915_dsc_bpp_support_write(struct file *file,
+						const char __user *ubuf,
+						size_t len, loff_t *offp)
+{
+	int dsc_bpp = 0;
+	int ret;
+	struct drm_connector *connector =
+		((struct seq_file *)file->private_data)->private;
+	struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+	if (len == 0)
+		return 0;
+
+	drm_dbg(&i915->drm,
+		"Copied %zu bytes from user to force BPP\n", len);
+
+	ret = kstrtoint_from_user(ubuf, len, 0, &dsc_bpp);
+
+	intel_dp->force_dsc_bpp = dsc_bpp;
+	if (ret < 0)
+		return ret;
+
+	*offp += len;
+	return len;
+}
+
+static int i915_dsc_bpp_support_open(struct inode *inode,
+					   struct file *file)
+{
+	return single_open(file, i915_dsc_bpp_support_show,
+			   inode->i_private);
+}
+
+static const struct file_operations i915_dsc_bpp_support_fops = {
+	.owner = THIS_MODULE,
+	.open = i915_dsc_bpp_support_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = i915_dsc_bpp_support_write
+};
+
 /**
  * intel_connector_debugfs_add - add i915 specific connector debugfs files
  * @connector: pointer to a registered drm_connector
@@ -2427,9 +2521,16 @@ int intel_connector_debugfs_add(struct drm_connector *connector)
 				    connector, &i915_hdcp_sink_capability_fops);
 	}
 
-	if ((DISPLAY_VER(dev_priv) >= 11 || IS_CANNONLAKE(dev_priv)) && ((connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort && !to_intel_connector(connector)->mst_port) || connector->connector_type == DRM_MODE_CONNECTOR_eDP))
+	if ((DISPLAY_VER(dev_priv) >= 11 || IS_CANNONLAKE(dev_priv)) &&
+	    ((connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort &&
+	      !to_intel_connector(connector)->mst_port) ||
+	     connector->connector_type == DRM_MODE_CONNECTOR_eDP)) {
 		debugfs_create_file("i915_dsc_fec_support", S_IRUGO, root,
 				    connector, &i915_dsc_fec_support_fops);
+		debugfs_create_file("i915_dsc_bpp_support", S_IRUGO,
+				    root, connector,
+				    &i915_dsc_bpp_support_fops);
+	}
 
 	/* Legacy panels doesn't lpsp on any platform */
 	if ((DISPLAY_VER(dev_priv) >= 9 || IS_HASWELL(dev_priv) ||
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d94f361b548b7..19d8d3eefbc27 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1612,6 +1612,7 @@ struct intel_dp {
 
 	/* Display stream compression testing */
 	bool force_dsc_en;
+	int force_dsc_bpp;
 
 	bool hobl_failed;
 	bool hobl_active;
-- 
2.25.1