Re: [PATCH 2/7] drm/msm/dp: reduce link rate if failed at link training 1

From: Stephen Boyd <swboyd@chromium.org>
To: khsieh@codeaurora.org
Cc: dri-devel@lists.freedesktop.org, robdclark@gmail.com,
	sean@poorly.run, abhinavk@codeaurora.org,
	aravindh@codeaurora.org, airlied@linux.ie, daniel@ffwll.ch,
	bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] drm/msm/dp: reduce link rate if failed at link training 1
Date: Thu, 15 Jul 2021 20:59:03 +0200	[thread overview]
Message-ID: <CAE-0n53M1XWa1Ng-+bBLQyKLRzabbTOofOMqknQbF+PWuE6=hw@mail.gmail.com> (raw)
In-Reply-To: <ef24f67a334698610b7b8e607a727b5d@codeaurora.org>

Quoting khsieh@codeaurora.org (2021-07-09 10:46:41)
> On 2021-07-08 00:33, Stephen Boyd wrote:
> >> +
> >> +static bool dp_ctrl_any_lane_cr_lose(struct dp_ctrl_private *ctrl,
> >> +                                       u8 *cr_status)
> >> +{
> >> +       int i;
> >> +       u8 status;
> >> +       int lane = ctrl->link->link_params.num_lanes;
> >> +
> >> +       for (i = 0; i < lane; i++) {
> >> +               status = cr_status[i / 2];
> >> +               status >>= ((i % 2) * 4);
> >> +               if (!(status & DP_LANE_CR_DONE))
> >> +                       return true;
> >> +       }
> >> +
> >> +       return false;
> >> +}
> >
> > Why not use !drm_dp_clock_recovery_ok() for dp_ctrl_any_lane_cr_lose()?
> ok,
>
> > And then move dp_ctrl_any_lane_cr_done() next to
> > drm_dp_clock_recovery_ok() and call it drm_dp_clock_recovery_any_ok()?
> no understand how it work, can you elaborate it more?

I'm suggesting to make a new function called
drm_dp_clock_recovery_any_ok(), written next to
drm_dp_clock_recovery_ok(). Then call it from here instead of implement
it locally in the qcom DP driver.