Re: [PATCH v3] drm/i915/dp: Increase idle pattern wait timeout to 2ms

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 04 Mar 2024, Shekhar Chauhan <shekhar.chauhan@intel.com> wrote:
> Currently, the driver is only waiting for 1ms for
> idle patterns. But starting from LNL and beyond,
> the MST wants the driver to wait for 1640us before

What does it mean that "the MST wants"?

> timing out (which we round up to 2ms).
>
> v1: Introduced the 2ms wait timeout.
> v2: Segregated the wait timeout for platforms before & after LNL.

I did not ask for this. I would rather all platforms used 2 ms. I even
said the original change looked fine. But I'd like it to be explained in
the commit message.

> v3: Fixed 2 cosmetic changes.
>
> BSpec: 68849
> Signed-off-by: Shekhar Chauhan <shekhar.chauhan@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index bea441590204..b59adb7685b8 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3677,12 +3677,19 @@ static void intel_ddi_set_idle_link_train(struct intel_dp *intel_dp,
>  	 */
>  	if (port == PORT_A && DISPLAY_VER(dev_priv) < 12)
>  		return;
> -
> -	if (intel_de_wait_for_set(dev_priv,
> -				  dp_tp_status_reg(encoder, crtc_state),
> -				  DP_TP_STATUS_IDLE_DONE, 1))
> +	if (DISPLAY_VER(dev_priv) >= 20) {
> +		if (intel_de_wait_for_set(dev_priv,
> +			dp_tp_status_reg(encoder, crtc_state),
> +			DP_TP_STATUS_IDLE_DONE, 2))
> +		drm_err(&dev_priv->drm,
> +			"Timed out waiting for DP idle patterns\n");
> +	} else {
> +		if (intel_de_wait_for_set(dev_priv,
> +			dp_tp_status_reg(encoder, crtc_state),
> +			DP_TP_STATUS_IDLE_DONE, 1))
>  		drm_err(&dev_priv->drm,
>  			"Timed out waiting for DP idle patterns\n");
> +	}

So I'd like you to go back to how it was originally.


>  }
>  
>  static bool intel_ddi_is_audio_enabled(struct drm_i915_private *dev_priv,

-- 
Jani Nikula, Intel