On Thu, Nov 26, 2015 at 10:55:53PM +0200, ville.syrjala@xxxxxxxxxxxxxxx wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> LPT/WPT only have transcoder A, so we shouldn't look at FIFO underruns
> for transocoder B/C. And more importnatnly we should not consider
> the state of underrun reporting for transcoders B/C when checking
> whether we can enable the south error interrupt.
>
> The whole thing is a bit of mess since we store the underrun reporting
> state for transcoder A under intel_crtc for pipe A, irrespective of
> which pipe may actually be driving the transcoder. But I figured trying
> to change that would result in more churn.
>
> Caveat: Still untested
>
> v2: Use HAS_PCH_LPT_H instead of HAS_DDI
> Use cpt_check_pch_fifo_underruns() on LPT-H/WPT-H too
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
I've battled hsw lpt fifo underrun issues last week and never seen a fifo
underrun on pipe B/C. Have you seen them anywhere really?
If not I think we can skip this patch here, since I think I tracked it all
down.
-Daniel
> ---
> drivers/gpu/drm/i915/intel_fifo_underrun.c | 27 ++++++++++++++++++++++-----
> 1 file changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_fifo_underrun.c b/drivers/gpu/drm/i915/intel_fifo_underrun.c
> index bda526660e20..3d3acc8b8367 100644
> --- a/drivers/gpu/drm/i915/intel_fifo_underrun.c
> +++ b/drivers/gpu/drm/i915/intel_fifo_underrun.c
> @@ -48,6 +48,14 @@
> * The code also supports underrun detection on the PCH transcoder.
> */
>
> +static bool cpt_transcoder_exists(struct drm_i915_private *dev_priv,
> + enum transcoder pch_transcoder)
> +{
> + /* LPT-H/WPT-H have only transcoder A */
> + return HAS_PCH_CPT(dev_priv) ||
> + (HAS_PCH_LPT_H(dev_priv) && pch_transcoder == TRANSCODER_A);
> +}
> +
> static bool ivb_can_enable_err_int(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -69,13 +77,16 @@ static bool ivb_can_enable_err_int(struct drm_device *dev)
> static bool cpt_can_enable_serr_int(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> - enum pipe pipe;
> - struct intel_crtc *crtc;
> + enum transcoder pch_transcoder;
>
> assert_spin_locked(&dev_priv->irq_lock);
>
> - for_each_pipe(dev_priv, pipe) {
> - crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
> + for_each_pipe(dev_priv, pch_transcoder) {
> + struct intel_crtc *crtc =
> + to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pch_transcoder]);
> +
> + if (!cpt_transcoder_exists(dev_priv, pch_transcoder))
> + continue;
>
> if (crtc->pch_fifo_underrun_disabled)
> return false;
> @@ -206,6 +217,9 @@ static void cpt_check_pch_fifo_underruns(struct intel_crtc *crtc)
>
> assert_spin_locked(&dev_priv->irq_lock);
>
> + if (!cpt_transcoder_exists(dev_priv, pch_transcoder))
> + return;
> +
> if ((serr_int & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) == 0)
> return;
>
> @@ -222,6 +236,9 @@ static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
>
> + if (!cpt_transcoder_exists(dev_priv, pch_transcoder))
> + return;
> +
> if (enable) {
> I915_WRITE(SERR_INT,
> SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
> @@ -436,7 +453,7 @@ void intel_check_pch_fifo_underruns(struct drm_i915_private *dev_priv)
> if (crtc->pch_fifo_underrun_disabled)
> continue;
>
> - if (HAS_PCH_CPT(dev_priv))
> + if (HAS_PCH_CPT(dev_priv) || HAS_PCH_LPT_H(dev_priv))
> cpt_check_pch_fifo_underruns(crtc);
> }
>
> --
> 2.4.10
>
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> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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