Re: [PATCH] drm/msm/dp: keep aux channel up when power of dp phy

[khsieh]

On 2021-05-26 21:29, Stephen Boyd wrote:
> General note, please Cc dri-devel on freedreno driver patches.
>
> Quoting Kuogee Hsieh (2021-05-26 16:49:49)
> > Aux channel is used to perform management function and should be
> > running in parallel with main link. Therefore should only power
> > down main link and keep aux channel running when power down phy.
> >
> > Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
> > ---
>
> Does this supersede the previous patch[1] or is it in addition to?
this is the addition one.

> [1]
> https://lore.kernel.org/r/1622052503-21158-1-git-send-email-khsieh@xxxxxxxxxxxxxx
>
> >  drivers/gpu/drm/msm/dp/dp_ctrl.c    |  4 ----
> >  drivers/phy/qualcomm/phy-qcom-qmp.c | 11 +++++++++--
> >  2 files changed, 9 insertions(+), 6 deletions(-)
>
> Given that it touches two subsystems the merge path is questionable.
ok, will separate it out
> > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
> > b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > index 5115c05..5f93c64 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > @@ -1844,10 +1844,6 @@ int dp_ctrl_off_link_stream(struct dp_ctrl 
> > *dp_ctrl)
> >
> >         phy_power_off(phy);
> >
> > -       /* aux channel down, reinit phy */
> > -       phy_exit(phy);
> > -       phy_init(phy);
> > -
> >         DRM_DEBUG_DP("DP off link/stream done\n");
> >         return ret;
> >  }
> > diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c 
> > b/drivers/phy/qualcomm/phy-qcom-qmp.c
> > index b122e63..567e32e 100644
> > --- a/drivers/phy/qualcomm/phy-qcom-qmp.c
> > +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
> > @@ -3214,12 +3214,19 @@ static int qcom_qmp_phy_power_off(struct phy 
> > *phy)
> >  {
> >         struct qmp_phy *qphy = phy_get_drvdata(phy);
> >         const struct qmp_phy_cfg *cfg = qphy->cfg;
> > +       u32 val;
> >
> >         clk_disable_unprepare(qphy->pipe_clk);
> >
> >         if (cfg->type == PHY_TYPE_DP) {
> > -               /* Assert DP PHY power down */
> > -               writel(DP_PHY_PD_CTL_PSR_PWRDN, qphy->pcs + 
> > QSERDES_V3_DP_PHY_PD_CTL);
> > +               /*
> > +                * Assert DP PHY LANE_0_1, LANE_2_3, PSR power down
> > +                * keep aux channel up
>
> Maybe say "keep aux channel up until phy_exit() is called" so we know
> how long it is supposed to stay on. And just to confirm, it is on in
> phy_init(), right?
yes, aux channel is on at phy_init
> > +                */
> > +               val = DP_PHY_PD_CTL_PWRDN | DP_PHY_PD_CTL_AUX_PWRDN |
> > +                       DP_PHY_PD_CTL_PLL_PWRDN | 
> > DP_PHY_PD_CTL_DP_CLAMP_EN |
> > +                       DP_PHY_PD_CTL_PSR_PWRDN;
> > +               writel(val, qphy->pcs + QSERDES_V3_DP_PHY_PD_CTL);
> >         } else {
> >                 /* PHY reset */
> >                 if (!cfg->no_pcs_sw_reset)