drm/i915: completely rewrite the Haswell PLL handling code

Problems with the previous code:
  - HDMI just uses WRPLL1 for everything, so dual head cases might not
    work sometimes.
  - At encoder->mode_set we just write the PLL register without doing
    any kind of check (e.g., check if the PLL is already being used).
  - There is no way to fail and return error codes at
    encoder->mode_set.
  - We write to PORT_CLK_SEL at mode_set and we never disable it.
  - Machines hang due to wrong clock enable/disable sequence.

So here we rewrite the code, making it a little more like the
pre-Haswell PLL mode set code:
  - Check PLL availability at ironlake_crtc_mode_set.
  - Try to use both WRPLLs.
  - Check if PLLs are used before actually trying to use them, and
    properly fail with error messages.
  - Enable/disable PORT_CLK_SEL at the right place.
  - Add some WARNs to check for bugs.

The next improvement will be to try to reuse PLLs if the timings
match, but this is content for another patch and it's already
documented with a TODO comment.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 5de365d70de..245319a4559 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -212,6 +212,7 @@ struct intel_crtc {
 
         /* We can share PLLs across outputs if the timings match */
         struct intel_pch_pll *pch_pll;
+        uint32_t ddi_pll_sel;
 };
 
 struct intel_plane {
@@ -586,5 +587,10 @@ extern void intel_ddi_disable_pipe_func(struct drm_i915_private *dev_priv,
                                         enum pipe pipe);
 extern void intel_ddi_enable_pipe_clock(struct intel_crtc *intel_crtc);
 extern void intel_ddi_disable_pipe_clock(struct intel_crtc *intel_crtc);
+extern void intel_ddi_setup_hw_pll_state(struct drm_device *dev);
+extern bool intel_ddi_pll_mode_set(struct drm_crtc *crtc, int clock);
+extern void intel_ddi_pre_enable(struct intel_encoder *intel_encoder);
+extern void intel_ddi_post_disable(struct intel_encoder *intel_encoder);
+extern void intel_ddi_put_crtc_pll(struct drm_crtc *crtc);
 
 #endif /* __INTEL_DRV_H__ */