drm/i915: clear up the fdi/dp set_m_n confusion

There's a rather decent confusion going on around transcoder m_n
values. So let's clarify:
- All dp encoders need this, either on the pch transcoder if it's a
  pch port, or on the cpu transcoder/pipe if it's a cpu port.
- fdi links need to have the right m_n values for the fdi link set in
  the cpu transcoder.

To handle the pch vs transcoder stuff a bit better, extract transcoder
set_m_n helpers. To make them simpler, set intel_crtc->cpu_transcoder
als in ironlake_crtc_mode_set, so that gen5+ (where the cpu m_n
registers are all at the same offset) can use it.

Haswell modeset is decently confused about dp vs. edp vs. fdi. dp vs.
edp works exactly the same as dp (since there's no pch dp any more),
so use that as a check. And only set up the fdi m_n values if we
really have a pch encoder present (which means we have a VGA encoder).

On ilk+ we've called ironlake_set_m_n both for cpu_edp and for pch
encoders. Now that dp_set_m_n handles all dp links (thanks to the
pch encoder check), we can ditch the cpu_edp stuff from the
fdi_set_m_n function.

Since the dp_m_n values are not readily available, we need to
carefully coax the edp values out of the encoder. Hence we can't (yet)
kill this superflous complexity.

v2: Rebase on top of the ivb fdi B/C check patch - we need to properly
clear intel_crtc->fdi_lane, otherwise those checks will misfire.

v3: Rebased on top of a s/IS_HASWELL/HAS_DDI/ patch from Paulo Zanoni.

v4: Drop the addition of has_dp_encoder, it's in the wrong patch (Jesse).

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2f451c2a14f5..c2a7f84b609d 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -192,6 +192,7 @@ struct intel_crtc_config {
 
 	bool dither;
 	int pipe_bpp;
+	struct intel_link_m_n dp_m_n;
 
 	/* Used by SDVO (and if we ever fix it, HDMI). */
 	unsigned pixel_multiplier;
@@ -640,6 +641,10 @@ extern void intel_init_clock_gating(struct drm_device *dev);
 extern void intel_write_eld(struct drm_encoder *encoder,
 			    struct drm_display_mode *mode);
 extern void intel_cpt_verify_modeset(struct drm_device *dev, int pipe);
+extern void intel_cpu_transcoder_set_m_n(struct intel_crtc *crtc,
+					 struct intel_link_m_n *m_n);
+extern void intel_pch_transcoder_set_m_n(struct intel_crtc *crtc,
+					 struct intel_link_m_n *m_n);
 extern void intel_prepare_ddi(struct drm_device *dev);
 extern void hsw_fdi_link_train(struct drm_crtc *crtc);
 extern void intel_ddi_init(struct drm_device *dev, enum port port);