From: khsieh@codeaurora.org
To: Stephen Boyd <swboyd@chromium.org>
Cc: agross@kernel.org, bjorn.andersson@linaro.org,
robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org,
abhinavk@codeaurora.org, aravindh@codeaurora.org,
freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/msm/dp: update is_connected status base on sink count at dp_pm_resume()
Date: Mon, 02 Aug 2021 09:10:06 -0700 [thread overview]
Message-ID: <781ad3c4973b3f8dd83933a451b266b9@codeaurora.org> (raw)
In-Reply-To: <CAE-0n51cNywB2ThQxqS4iX-d7wR+rYXt8P33o9cUq9J6tT915A@mail.gmail.com>
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 <khsieh@codeaurora.org>
>> ---
>> 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;
prev parent reply other threads:[~2021-08-02 16:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 21:30 [PATCH] drm/msm/dp: update is_connected status base on sink count at dp_pm_resume() Kuogee Hsieh
2021-07-28 21:30 ` Kuogee Hsieh
2021-07-30 18:57 ` Stephen Boyd
2021-08-02 16:10 ` khsieh [this message]
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