[PATCH 4/4] drm/i915: debug messge for lossy sdvo dtd -> drm mode conversion

[Daniel Vetter]

We round-trip quite often from sdvo dtd timings through drm mode back
to sdvo dtd timings, e.g. due to mode_fixup. Add an informational
message that tells us when we lose things on the way.

Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_sdvo.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index a6de3a6..2c14e37 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -804,6 +804,11 @@ static void intel_sdvo_get_mode_from_dtd(struct drm_display_mode * mode,
 
 	mode->clock = dtd->part1.clock * 10;
 
+	if (dtd->part2.dtd_flags & ~(0x2 | 0x4) || dtd->part2.sdvo_flags)
+		DRM_INFO("Potentially losing SDVO DTD parameters, "
+			 "dtd_flags: 0x%02x, sdvo_flags: 0x%02x\n",
+			 dtd->part2.dtd_flags, dtd->part2.sdvo_flags);
+
 	mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
 	if (dtd->part2.dtd_flags & 0x2)
 		mode->flags |= DRM_MODE_FLAG_PHSYNC;
-- 
1.7.9.1