Re: [PATCH 08/14] drm/i915: Disable FIFO underrun reporting around IBX transcoder B workaround

Jesse Barnes
2015-10-29T19:37:44Z

On 10/29/2015 12:25 PM, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Doing the IBX transcoder B workaround causes underruns on
> pipe/transcoder A. Just hide them by disabling underrun reporting for
> pipe A around the workaround.
>
> It might be possible to avoid the underruns by moving the workaround
> to be applied only when enabling pipe A. But I was too lazy to try it
> right now, and the current method has been proven to work, so didn't
> want to change it too hastily.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 11 +++++++++++
> drivers/gpu/drm/i915/intel_drv.h | 9 +++++++++
> drivers/gpu/drm/i915/intel_hdmi.c | 11 +++++++++++
> drivers/gpu/drm/i915/intel_sdvo.c | 11 +++++++++++
> 4 files changed, 42 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 8287df4..4a0fb63 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3957,6 +3957,13 @@ intel_dp_link_down(struct intel_dp *intel_dp)
> * matching HDMI port to be enabled on transcoder A.
> */
> if (HAS_PCH_IBX(dev) && crtc->pipe == PIPE_B && port != PORT_A) {
> + /*
> + * We get CPU/PCH FIFO underruns on the other pipe when
> + * doing the workaround. Sweep them under the rug.
> + */
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> +
> /* always enable with pattern 1 (as per spec) */
> DP &= ~(DP_PIPEB_SELECT | DP_LINK_TRAIN_MASK);
> DP |= DP_PORT_EN | DP_LINK_TRAIN_PAT_1;
> @@ -3966,6 +3973,10 @@ intel_dp_link_down(struct intel_dp *intel_dp)
> DP &= ~DP_PORT_EN;
> I915_WRITE(intel_dp->output_reg, DP);
> POSTING_READ(intel_dp->output_reg);
> +
> + intel_wait_for_vblank_if_active(dev_priv->dev, PIPE_A);
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> }
>
> msleep(intel_dp->panel_power_down_delay);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 72cc272..35f1457 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1073,6 +1073,15 @@ intel_wait_for_vblank(struct drm_device *dev, int pipe)
> {
> drm_wait_one_vblank(dev, pipe);
> }
> +static inline void
> +intel_wait_for_vblank_if_active(struct drm_device *dev, int pipe)
> +{
> + const struct intel_crtc *crtc =
> + to_intel_crtc(intel_get_crtc_for_pipe(dev, pipe));
> +
> + if (crtc->active)
> + intel_wait_for_vblank(dev, pipe);
> +}
> int ironlake_get_lanes_required(int target_clock, int link_bw, int bpp);
> void vlv_wait_port_ready(struct drm_i915_private *dev_priv,
> struct intel_digital_port *dport,
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 013bd7d..bccbe70 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1108,6 +1108,13 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
> * matching DP port to be enabled on transcoder A.
> */
> if (HAS_PCH_IBX(dev) && crtc->pipe == PIPE_B) {
> + /*
> + * We get CPU/PCH FIFO underruns on the other pipe when
> + * doing the workaround. Sweep them under the rug.
> + */
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> +
> temp &= ~SDVO_PIPE_B_SELECT;
> temp |= SDVO_ENABLE;
> /*
> @@ -1122,6 +1129,10 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
> temp &= ~SDVO_ENABLE;
> I915_WRITE(intel_hdmi->hdmi_reg, temp);
> POSTING_READ(intel_hdmi->hdmi_reg);
> +
> + intel_wait_for_vblank_if_active(dev_priv->dev, PIPE_A);
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> }
>
> intel_hdmi->set_infoframes(&encoder->base, false, NULL);
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> index c42b636..267e6cb 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -1464,12 +1464,23 @@ static void intel_disable_sdvo(struct intel_encoder *encoder)
> * matching DP port to be enabled on transcoder A.
> */
> if (HAS_PCH_IBX(dev_priv) && crtc->pipe == PIPE_B) {
> + /*
> + * We get CPU/PCH FIFO underruns on the other pipe when
> + * doing the workaround. Sweep them under the rug.
> + */
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, false);
> +
> temp &= ~SDVO_PIPE_B_SELECT;
> temp |= SDVO_ENABLE;
> intel_sdvo_write_sdvox(intel_sdvo, temp);
>
> temp &= ~SDVO_ENABLE;
> intel_sdvo_write_sdvox(intel_sdvo, temp);
> +
> + intel_wait_for_vblank_if_active(dev_priv->dev, PIPE_A);
> + intel_set_cpu_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> + intel_set_pch_fifo_underrun_reporting(dev_priv, PIPE_A, true);
> }
> }
>
>

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>