Re: [PATCH 6/7] drm/i915: Try harder during dp pattern 1 link training

Chris Wilson
2011-11-02T09:12:21Z

On Tue, 1 Nov 2011 23:20:29 -0700, Keith Packard <keithp@keithp.com> wrote:
> Instead of going through the sequence just once, run through the whole
> set up to 5 times to see if something can work. This isn't part of the
> DP spec, but the BIOS seems to do it, and given that link training
> failure is so bad, it seems reasonable to follow suit.
>
> Signed-off-by: Keith Packard <keithp@keithp.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 41 +++++++++++++++++++++++++-------------
> 1 files changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 6be6a04..bf20a35 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1576,8 +1576,9 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
>
> ret = intel_dp_aux_native_write(intel_dp,
> DP_TRAINING_LANE0_SET,
> - intel_dp->train_set, 4);
> - if (ret != 4)
> + intel_dp->train_set,
> + intel_dp->lane_count);
> + if (ret != intel_dp->lane_count)
> return false;

This would seem to be a separate chunk to initiate training on only the
lanes we intend to use.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre