[Intel-gfx] [PATCH] drm/i915: Document the use of requested_mode, adjusted_mode, and pipe_src_{w, h}

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Try to clarify the purpose of the two different modes we keep, and the
pipe source size.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a71b47c..75e86da 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -211,9 +211,19 @@ struct intel_crtc_config {
 #define PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS (1<<0) /* unreliable sync mode.flags */
 	unsigned long quirks;
 
+	/* User requested mode, only valid as a starting point to
+	 * compute adjusted_mode, except in the case of (S)DVO where
+	 * it's also for the output timings of the (S)DVO chip.
+	 * adjusted_mode will then correspond to the S(DVO) chip's
+	 * preferred input timings. */
 	struct drm_display_mode requested_mode;
+	/* Actual pipe timings ie. what we
+	 * program into the pipe timing registers. */
 	struct drm_display_mode adjusted_mode;
 
+	/* Pipe source size (ie. panel fitter input size)
+	 * All planes will be positioned inside this space,
+	 * and get clipped at the edges. */
 	int pipe_src_w, pipe_src_h;
 
 	/* Whether to set up the PCH/FDI. Note that we never allow sharing
-- 
1.8.1.5