[PATCH 1/3] drm/i915/display/debugfs: Add connector debugfs for "output_bpc"

[Bhanuprakash Modem]

This new debugfs will expose the connector's max supported bpc
and the bpc currently using. It is very useful for verifying
whether we enter the correct output color depth from IGT.

Example:
cat /sys/kernel/debug/dri/0/DP-1/output_bpc
Current: 8
Maximum: 10

V2: Add connector's max bpc to i915_display_info

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Swati Sharma <swati2.sharma at intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
 .../drm/i915/display/intel_display_debugfs.c  | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index 452d773fd..6c3954479 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -590,6 +590,8 @@ static void intel_connector_info(struct seq_file *m,
 	seq_puts(m, "\tHDCP version: ");
 	intel_hdcp_info(m, intel_connector);
 
+	seq_printf(m, "\tmax bpc: %u\n", connector->display_info.bpc);
+
 	intel_panel_info(m, intel_connector);
 
 	seq_printf(m, "\tmodes:\n");
@@ -2202,6 +2204,29 @@ static const struct file_operations i915_dsc_bpp_fops = {
 	.write = i915_dsc_bpp_write
 };
 
+/*
+ * Returns the Current CRTC's bpc.
+ * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
+ */
+static int i915_current_bpc_show(struct seq_file *m, void *data)
+{
+	struct intel_crtc *crtc = to_intel_crtc(m->private);
+	struct intel_crtc_state *crtc_state;
+	int ret;
+
+	ret = drm_modeset_lock_single_interruptible(&crtc->base.mutex);
+	if (ret)
+		return ret;
+
+	crtc_state = to_intel_crtc_state(crtc->base.state);
+	seq_printf(m, "Current: %u\n", crtc_state->pipe_bpp / 3);
+
+	drm_modeset_unlock(&crtc->base.mutex);
+
+	return ret;
+}
+DEFINE_SHOW_ATTRIBUTE(i915_current_bpc);
+
 /**
  * intel_connector_debugfs_add - add i915 specific connector debugfs files
  * @connector: pointer to a registered drm_connector
@@ -2272,4 +2297,7 @@ void intel_crtc_debugfs_add(struct drm_crtc *crtc)
 
 	crtc_updates_add(crtc);
 	intel_fbc_crtc_debugfs_add(to_intel_crtc(crtc));
+
+	debugfs_create_file("i915_current_bpc", 0444, crtc->debugfs_entry, crtc,
+			    &i915_current_bpc_fops);
 }
-- 
2.35.1