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

[Yakir Yang <ykk@xxxxxxxxxxxxxx>]

Sean,

Thanks for your comments.

On 09/07/2016 03:51 AM, Sean Paul wrote:
> On Fri, Aug 26, 2016 at 6:19 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote:
> > Make sure the request PSR state could effect in analogix_dp_send_psr_spd()
> > function, or printing the error Sink PSR state if we failed to effect
> > the request PSR setting.
> >
> > Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  6 ++---
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  4 ++--
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 26 ++++++++++++++++++++--
> >   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 efac8ab..5a37de8 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > @@ -115,8 +115,7 @@ 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);
> >
> > @@ -138,8 +137,7 @@ 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 473b980..f617a9d 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > @@ -283,7 +283,7 @@ 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);
> >
> >   #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 52c1b6b..505e9d8 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > @@ -1328,9 +1328,11 @@ 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 char sink;
> u8
Done
> >          unsigned int val;
> >
> >          /* don't send info frame */
> > @@ -1372,4 +1374,24 @@ 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 + msecs_to_jiffies(100);
> Pull 100 out into a #define
Done
> > +       while (1) {
> > +               analogix_dp_read_byte_from_dpcd(dp, DP_PSR_STATUS, &sink);
> You should be checking return value here.
Done
> > +
> > +               if (vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB)
> > +                       break;
> > +
> > +               if (!vsc->DB1 && sink == DP_PSR_SINK_INACTIVE)
> > +                       break;
> > +
> > +               if (time_after(jiffies, timeout)) {
> > +                       dev_warn(dp->dev, "Failed to effect PSR: %x", sink);
> > +                       return -EBUSY;
> -ETIMEDOUT is more appropriate
Done
> > +               }
> > +
> > +               usleep_range(1000, 1500);
> > +       }
> The while(1) loop is a little scary. I'd rather do:
>
> while (time_before(jiffies, timeout)) {
>                 ret = analogix_dp_read_byte_from_dpcd(dp, DP_PSR_STATUS, &sink);
>                 if (ret != 1) {
>                         DRM_DEV_ERROR(dp->dev, "PSR_STATUS read failed
> ret=%d", ret);
>                         return ret;
>                 }
>
>                 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 effect PSR: %x", sink);
> return -ETIMEDOUT;

Thanks for your code.

- Yakir

> > +
> > +       return 0;
> >   }
> > --
> > 1.9.1
> >
> >
> > --
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