Re: [PATCH v3 3/3] drm/bridge: analogix_dp: detect Sink PSR state after configuring the PSR

[Yakir Yang]

Hi Sean,

On 09/12/2016 09:52 PM, Sean Paul wrote:
> On Fri, Sep 9, 2016 at 5:45 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote:
> > Make sure the request PSR state takes effect in analogix_dp_send_psr_spd()
> > function, or print the sink PSR error state if we failed to apply the
> > requested PSR setting.
> >
> > Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
> > ---
> > Changes in v3:
> > - Update commit message
> > - Add DP_TIMEOUT_PSR_LOOP_MS marcos
> > - Correct the return values of analogix_dp_send_psr_spd()
> >
> > Changes in v2:
> > - A bunch of good fixes from Sean
> >
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  6 ++----
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  5 +++--
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 25 ++++++++++++++++++++--
> >   3 files changed, 28 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > index 5fe3982..c0ce16a 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > @@ -116,8 +116,7 @@ int analogix_dp_enable_psr(struct device *dev)
> >          psr_vsc.DB0 = 0;
> >          psr_vsc.DB1 = EDP_VSC_PSR_STATE_ACTIVE | EDP_VSC_PSR_CRC_VALUES_VALID;
> >
> > -       analogix_dp_send_psr_spd(dp, &psr_vsc);
> > -       return 0;
> > +       return analogix_dp_send_psr_spd(dp, &psr_vsc);
> >   }
> >   EXPORT_SYMBOL_GPL(analogix_dp_enable_psr);
> >
> > @@ -139,8 +138,7 @@ int analogix_dp_disable_psr(struct device *dev)
> >          psr_vsc.DB0 = 0;
> >          psr_vsc.DB1 = 0;
> >
> > -       analogix_dp_send_psr_spd(dp, &psr_vsc);
> > -       return 0;
> > +       return analogix_dp_send_psr_spd(dp, &psr_vsc);
> >   }
> >   EXPORT_SYMBOL_GPL(analogix_dp_disable_psr);
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > index d564e90..a27f1e3 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > @@ -20,6 +20,7 @@
> >   #define MAX_EQ_LOOP 5
> >
> >   #define DP_TIMEOUT_LOOP_MS                     msecs_to_jiffies(1)
> > +#define DP_TIMEOUT_PSR_LOOP_MS                 msecs_to_jiffies(300)
> Same comment here re: units.
>
> 300ms seems like a really long time. Why does it take this long?

This magic number '300ms' just come from my test, I haven't found the 
description in eDP 1.4a Spec about what exact time should Sink take to 
entry PSR.

- Yakir

> Sean
>
>
> >   /* DP_MAX_LANE_COUNT */
> >   #define DPCD_ENHANCED_FRAME_CAP(x)             (((x) >> 7) & 0x1)
> > @@ -248,8 +249,8 @@ void analogix_dp_config_video_slave_mode(struct analogix_dp_device *dp);
> >   void analogix_dp_enable_scrambling(struct analogix_dp_device *dp);
> >   void analogix_dp_disable_scrambling(struct analogix_dp_device *dp);
> >   void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp);
> > -void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> > -                             struct edp_vsc_psr *vsc);
> > +int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> > +                            struct edp_vsc_psr *vsc);
> >   ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
> >                               struct drm_dp_aux_msg *msg);
> >   #endif /* _ANALOGIX_DP_CORE_H */
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > index 15a4cf0..7fd4ed0 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > @@ -1004,10 +1004,12 @@ void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp)
> >          writel(PSR_VID_CRC_ENABLE, dp->reg_base + ANALOGIX_DP_CRC_CON);
> >   }
> >
> > -void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> > -                             struct edp_vsc_psr *vsc)
> > +int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> > +                            struct edp_vsc_psr *vsc)
> >   {
> > +       unsigned long timeout;
> >          unsigned int val;
> > +       u8 sink;
> >
> >          /* don't send info frame */
> >          val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> > @@ -1048,6 +1050,25 @@ void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> >          val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> >          val |= IF_EN;
> >          writel(val, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> > +
> > +       timeout = jiffies + DP_TIMEOUT_PSR_LOOP_MS;
> > +       while (time_before(jiffies, timeout)) {
> > +               val = drm_dp_dpcd_readb(&dp->aux, DP_PSR_STATUS, &sink);
> > +               if (val != 1) {
> > +                       dev_err(dp->dev, "PSR_STATUS read failed ret=%d", val);
> > +                       return -EBUSY;
> > +               }
> > +
> > +               if ((vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB) ||
> > +                   (!vsc->DB1 && sink == DP_PSR_SINK_INACTIVE))
> > +                       return 0;
> > +
> > +               usleep_range(1000, 1500);
> > +       }
> > +
> > +       dev_warn(dp->dev, "Failed to apply PSR, sink state was [%x]", sink);
> > +
> > +       return -ETIMEDOUT;
> >   }
> >
> >   ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
> > --
> > 1.9.1
> >
> >
> > --
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