On Wed, Jun 24, 2020 at 03:11:08PM -0700, Manasi Navare wrote:
> Based on the platform, Bspec expects us to wait or poll with
> timeout for DDI BUF IDLE bit to be set to 0 (non idle) or get active
> after enabling DDI_BUF_CTL.
>
> v3:
> * Add a new function _active for DDI BUF CTL to be non idle (Ville)
> v2:
> * Based on platform, fixed delay or poll (Ville)
> * Use a helper to do this (Imre, Ville)
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 7d5c8ab88fc4..ff6b1e9d1b4e 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -1195,6 +1195,20 @@ static void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
> port_name(port));
> }
>
> +static void intel_wait_ddi_buf_active(struct drm_i915_private *dev_priv,
> + enum port port)
> +{
> + if (INTEL_GEN(dev_priv) <= 9) {
Didn't we want the poll approach for glk+?
> + usleep_range(600, 1000);
> + return;
> + }
> +
> + if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> + DDI_BUF_IS_IDLE), 600))
> + drm_err(&dev_priv->drm, "Timeout waiting for DDI BUF %c to get active\n",
> + port_name(port));
> +}
> +
> static u32 hsw_pll_to_ddi_pll_sel(const struct intel_shared_dpll *pll)
> {
> switch (pll->info->id) {
> @@ -4020,7 +4034,7 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
> intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>
> - udelay(600);
> + intel_wait_ddi_buf_active(dev_priv, port);
Missed the FDI case.
Also we're still missing this for HDMI, on icl+ I think? Can't quite
remember if that was where the spec started to demand it.
> }
>
> static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> --
> 2.19.1
--
Ville Syrjälä
Intel
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