2021-07-28 21:33:53

by Kuogee Hsieh

Subject: [PATCH] drm/msm/dp: update is_connected status base on sink count at dp_pm_resume()

Currently at dp_pm_resume() is_connected state is decided base on hpd connection
status only. This will put is_connected in wrongly "true" state at the scenario
that dongle attached to DUT but without hmdi cable connecting to it. Fix this
problem by adding read sink count from dongle and decided is_connected state base
on both sink count and hpd connection status.

Signed-off-by: Kuogee Hsieh <[email protected]>
---
drivers/gpu/drm/msm/dp/dp_display.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 2b660e9..9bcb261 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1308,6 +1308,17 @@ static int dp_display_remove(struct platform_device *pdev)
return 0;
}

+static int dp_get_sink_count(struct dp_display_private *dp)
+{
+ u8 sink_count;
+
+ sink_count = drm_dp_read_sink_count(dp->aux);
+ if (sink_count < 0)
+ return 0;
+
+ return sink_count;
+}
+
static int dp_pm_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
@@ -1327,14 +1338,22 @@ static int dp_pm_resume(struct device *dev)

dp_catalog_ctrl_hpd_config(dp->catalog);

- status = dp_catalog_link_is_connected(dp->catalog);
+ /*
+ * set sink to normal operation mode -- D0
+ * before dpcd read
+ */
+ dp_link_psm_config(dp->link, &dp->panel->link_info, false);

+ if ((status = dp_catalog_link_is_connected(dp->catalog)))
+ dp->link->sink_count = dp_get_sink_count(dp);
+ else
+ dp->link->sink_count = 0;
/*
* can not declared display is connected unless
* HDMI cable is plugged in and sink_count of
* dongle become 1
*/
- if (status && dp->link->sink_count)
+ if (dp->link->sink_count)
dp->dp_display.is_connected = true;
else
dp->dp_display.is_connected = false;
--
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a Linux Foundation Collaborative Project

2021-07-30 18:59:30

by Stephen Boyd

Subject: Re: [PATCH] drm/msm/dp: update is_connected status base on sink count at dp_pm_resume()

Quoting Kuogee Hsieh (2021-07-28 14:30:54)
> Currently at dp_pm_resume() is_connected state is decided base on hpd connection
> status only. This will put is_connected in wrongly "true" state at the scenario
> that dongle attached to DUT but without hmdi cable connecting to it. Fix this
> problem by adding read sink count from dongle and decided is_connected state base
> on both sink count and hpd connection status.
>

Please add a Fixes tag.

> Signed-off-by: Kuogee Hsieh <[email protected]>
> ---
> drivers/gpu/drm/msm/dp/dp_display.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 2b660e9..9bcb261 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1308,6 +1308,17 @@ static int dp_display_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static int dp_get_sink_count(struct dp_display_private *dp)
> +{
> + u8 sink_count;
> +
> + sink_count = drm_dp_read_sink_count(dp->aux);

drm_dp_read_sink_count() returns an int, not a u8. Comparing a u8 to
less than zero doesn't make any sense as it isn't signed.

> + if (sink_count < 0)
> + return 0;
> +
> + return sink_count;
> +}

We can drop this function and just have an int count in dp_pm_resume()
that is compared to < 0 and then ignored.

> +
> static int dp_pm_resume(struct device *dev)
> {
> struct platform_device *pdev = to_platform_device(dev);
> @@ -1327,14 +1338,22 @@ static int dp_pm_resume(struct device *dev)
>
> dp_catalog_ctrl_hpd_config(dp->catalog);
>
> - status = dp_catalog_link_is_connected(dp->catalog);
> + /*
> + * set sink to normal operation mode -- D0
> + * before dpcd read
> + */
> + dp_link_psm_config(dp->link, &dp->panel->link_info, false);
>
> + if ((status = dp_catalog_link_is_connected(dp->catalog)))
> + dp->link->sink_count = dp_get_sink_count(dp);

Do we need to call drm_dp_read_sink_count_cap() as well?

> + else
> + dp->link->sink_count = 0;
> /*
> * can not declared display is connected unless
> * HDMI cable is plugged in and sink_count of
> * dongle become 1
> */
> - if (status && dp->link->sink_count)

Is 'status' used anymore? If not, please remove it.

> + if (dp->link->sink_count)
> dp->dp_display.is_connected = true;
> else
> dp->dp_display.is_connected = false;

2021-08-02 16:12:51

by Kuogee Hsieh

Subject: Re: [PATCH] drm/msm/dp: update is_connected status base on sink count at dp_pm_resume()

On 2021-07-30 11:57, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-07-28 14:30:54)
>> Currently at dp_pm_resume() is_connected state is decided base on hpd
>> connection
>> status only. This will put is_connected in wrongly "true" state at the
>> scenario
>> that dongle attached to DUT but without hmdi cable connecting to it.
>> Fix this
>> problem by adding read sink count from dongle and decided is_connected
>> state base
>> on both sink count and hpd connection status.
>>
>
> Please add a Fixes tag.
>
>> Signed-off-by: Kuogee Hsieh <[email protected]>
>> ---
>> drivers/gpu/drm/msm/dp/dp_display.c | 23 +++++++++++++++++++++--
>> 1 file changed, 21 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
>> b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 2b660e9..9bcb261 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -1308,6 +1308,17 @@ static int dp_display_remove(struct
>> platform_device *pdev)
>> return 0;
>> }
>>
>> +static int dp_get_sink_count(struct dp_display_private *dp)
>> +{
>> + u8 sink_count;
>> +
>> + sink_count = drm_dp_read_sink_count(dp->aux);
>
> drm_dp_read_sink_count() returns an int, not a u8. Comparing a u8 to
> less than zero doesn't make any sense as it isn't signed.
>
>> + if (sink_count < 0)
>> + return 0;
>> +
>> + return sink_count;
>> +}
>
> We can drop this function and just have an int count in dp_pm_resume()
> that is compared to < 0 and then ignored.
>
>> +
>> static int dp_pm_resume(struct device *dev)
>> {
>> struct platform_device *pdev = to_platform_device(dev);
>> @@ -1327,14 +1338,22 @@ static int dp_pm_resume(struct device *dev)
>>
>> dp_catalog_ctrl_hpd_config(dp->catalog);
>>
>> - status = dp_catalog_link_is_connected(dp->catalog);
>> + /*
>> + * set sink to normal operation mode -- D0
>> + * before dpcd read
>> + */
>> + dp_link_psm_config(dp->link, &dp->panel->link_info, false);
>>
>> + if ((status = dp_catalog_link_is_connected(dp->catalog)))
>> + dp->link->sink_count = dp_get_sink_count(dp);
>
> Do we need to call drm_dp_read_sink_count_cap() as well?
no, we only need sink_count
>
>> + else
>> + dp->link->sink_count = 0;
>> /*
>> * can not declared display is connected unless
>> * HDMI cable is plugged in and sink_count of
>> * dongle become 1
>> */
>> - if (status && dp->link->sink_count)
>
> Is 'status' used anymore? If not, please remove it.
Yes, it still used which used to decided to perform dpcd read sink count
or not
>
>> + if (dp->link->sink_count)
>> dp->dp_display.is_connected = true;
>> else
>> dp->dp_display.is_connected = false;