Re: [PATCH] drm/i915/lnl: Modeset sequence change for DP on LNL

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

On Wed, 28 Feb 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
> timing out (which we round up to 2ms).

The change is not specific to LNL, so the subject should not claim
so. Moreover, "modeset sequence change" is extremely vague. Need to be
more specific. Something like:

"drm/i915/dp: increase idle done wait timeout to 2 ms"

And then the commit message would have the rationale about LNL, and why
it makes sense to bump the timeout also for non-LNL DDI platforms
instead of just LNL and later.

The change itself looks fine. But we merge hundreds of patches per
release, and the commit messages absolutely need to accurately describe
what's being done and why.


BR,
Jani.


>
> BSpec: 68849
> Signed-off-by: Shekhar Chauhan <shekhar.chauhan@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index bea441590204..05ba3642d486 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3680,7 +3680,7 @@ static void intel_ddi_set_idle_link_train(struct intel_dp *intel_dp,
>  
>  	if (intel_de_wait_for_set(dev_priv,
>  				  dp_tp_status_reg(encoder, crtc_state),
> -				  DP_TP_STATUS_IDLE_DONE, 1))
> +				  DP_TP_STATUS_IDLE_DONE, 2))
>  		drm_err(&dev_priv->drm,
>  			"Timed out waiting for DP idle patterns\n");
>  }

-- 
Jani Nikula, Intel