linux-kernel - Re: [PATCH] drm/msm/dp: handle irq_hpd with sink

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Date:   Wed, 12 May 2021 10:57:26 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Kuogee Hsieh <khsieh@...eaurora.org>, agross@...nel.org,
        bjorn.andersson@...aro.org, robdclark@...il.com, sean@...rly.run,
        abhinavk@...eaurora.org, aravindh@...eaurora.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/msm/dp: handle irq_hpd with sink_count = 0 correctly

On 10-05-21, 11:15, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-05-05 14:52:01)
> > @@ -1414,6 +1416,10 @@ void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
> >         phy = dp_io->phy;
> >
> >         dp_catalog_ctrl_enable_irq(ctrl->catalog, false);
> > +
> > +       if (phy->power_count)
> > +               phy_power_off(phy);
> > +
> >         phy_exit(phy);
> >
> >         DRM_DEBUG_DP("Host deinitialized successfully\n");
> > @@ -1445,7 +1451,6 @@ static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
> >
> >         dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, false);
> >         opts_dp->lanes = ctrl->link->link_params.num_lanes;
> > -       phy_configure(phy, &dp_io->phy_opts);
> >         /*
> >          * Disable and re-enable the mainlink clock since the
> >          * link clock might have been adjusted as part of the
> > @@ -1456,9 +1461,13 @@ static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl)
> >                 DRM_ERROR("Failed to disable clocks. ret=%d\n", ret);
> >                 return ret;
> >         }
> > -       phy_power_off(phy);
> > -       /* hw recommended delay before re-enabling clocks */
> > -       msleep(20);
> > +
> > +       if (phy->power_count) {
> 
> I don't believe members of 'phy' are supposed to be looked at by various
> phy consumer drivers. Vinod, is that right?

That is correct, we should not be doing that. And IMO this code is
redundant, the phy core will check power_count and invoke drivers
.power_off accordingly, so should be removed...

Thanks
-- 
~Vinod