[PATCH v2 2/2] drm/bridge: analogix_dp: detect Sink PSR state after configuring the PSR

[Yakir Yang]

On 09/08/2016 10:12 PM, Sean Paul wrote:
> On Wed, Sep 7, 2016 at 11:48 PM, Yakir Yang <ykk at rock-chips.com> 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.
>>
>
> Let's change to:
>
> 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.
Done,
>> Signed-off-by: Yakir Yang <ykk at rock-chips.com>
>> ---
>> 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 |  4 ++--
>>   drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 25 ++++++++++++++++++++--
>>   3 files changed, 27 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 a15f076..6c07a50 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
>> @@ -247,8 +247,8 @@ 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 a4d17b8..09d703b 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 + msecs_to_jiffies(DP_TIMEOUT_LOOP_COUNT);
> Mismatched units here. DP_TIMEOUT_LOOP_COUNT is defined as number of
> retries, whereas you're using it as number of ms. Fortunately, the
> retry number is so high that this works out :)
>
> In a separate patch preceding this one, can you change
> DP_TIMEOUT_LOOP_COUNT to DP_TIMEOUT_LOOP_MS and alter the other
> timeout loops to use time_before() like this one instead of blindly
> looping 100 times? After that, you can use DP_TIMEOUT_LOOP_MS here.

Done, and after do some experiments, I found we need to set the timeout 
to 300ms. Cause in some case we would take about 290ms here to get the 
right psr state.


>> +       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 val;
> Ok, since this is my snippet this comment is my fault, and I apologize
> for that :). However, this could return 0. If drm_dp_dpcd_readb
> returns 0, you probably want to retry (same as -EBUSY).
done, just return -EBUSY
>
>> +               }
>> +
>> +               if (vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB ||
>> +                   !vsc->DB1 && sink == DP_PSR_SINK_INACTIVE)
>> +                       break;
>> +
>> +               usleep_range(1000, 1500);
>> +       }
>> +
>> +       dev_warn(dp->dev, "Failed to effect PSR: %x", sink);
> Nit: I think you want to say "PSR failed to take effect" or "Failed to
> apply PSR"
Done

- Yakir
> Sean
>
>> +
>> +       return -ETIMEDOUT;
>>   }
>>
>>   ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
>> --
>> 1.9.1
>>
>>
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