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Subject: Re: [PATCH 2/4] drm/hisilicon: Code cleanup for hibmc_drv_vdac
To:     Xinliang Liu <xinliang.liu@linaro.org>,
        Tian Tao <tiantao6@hisilicon.com>
Cc:     David Airlie <airlied@linux.ie>,
        Chen Feng <puck.chen@hisilicon.com>,
        lkml <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>, linuxarm@huawei.com,
        kraxel@redhat.com, alexander.deucher@amd.com, tglx@linutronix.de
References: <1583466184-7060-1-git-send-email-tiantao6@hisilicon.com>
 <1583466184-7060-5-git-send-email-tiantao6@hisilicon.com>
 <CAKoKPbwgiFdvfLHXoD9wPJvJ5yzMMrxNEEJUArSEvNdx46+m9Q@mail.gmail.com>
From:   Thomas Zimmermann <tzimmermann@suse.de>
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Message-ID: <07040b3e-9137-10ef-9a18-381b0316fef9@suse.de>
Date:   Fri, 3 Apr 2020 09:00:17 +0200
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From: Thomas Zimmermann <tzimmermann@suse.de>
To: Xinliang Liu <xinliang.liu@linaro.org>, Tian Tao <tiantao6@hisilicon.com>
Cc: David Airlie <airlied@linux.ie>, Chen Feng <puck.chen@hisilicon.com>,
 lkml <linux-kernel@vger.kernel.org>,
 dri-devel <dri-devel@lists.freedesktop.org>, linuxarm@huawei.com,
 kraxel@redhat.com, alexander.deucher@amd.com, tglx@linutronix.de
Message-ID: <07040b3e-9137-10ef-9a18-381b0316fef9@suse.de>
Subject: Re: [PATCH 2/4] drm/hisilicon: Code cleanup for hibmc_drv_vdac
References: <1583466184-7060-1-git-send-email-tiantao6@hisilicon.com>
 <1583466184-7060-5-git-send-email-tiantao6@hisilicon.com>
 <CAKoKPbwgiFdvfLHXoD9wPJvJ5yzMMrxNEEJUArSEvNdx46+m9Q@mail.gmail.com>
In-Reply-To: <CAKoKPbwgiFdvfLHXoD9wPJvJ5yzMMrxNEEJUArSEvNdx46+m9Q@mail.gmail.com>

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Hi

Am 03.04.20 um 04:26 schrieb Xinliang Liu:
> Hi Tao,
>=20
> On Fri, 6 Mar 2020 at 11:44, Tian Tao <tiantao6@hisilicon.com> wrote:
>>
>> code cleanup for hibmc_drv_vdac.c, no actual function changes.
>>
>> Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
>> Signed-off-by: Gong junjie <gongjunjie2@huawei.com>
>> ---
>>  drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c | 49 ++++++++-------=
---------
>>  1 file changed, 16 insertions(+), 33 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c b/driver=
s/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
>> index 678ac2e..f0e6bb8 100644
>> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
>> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_vdac.c
>> @@ -52,32 +52,6 @@ static const struct drm_connector_funcs hibmc_conne=
ctor_funcs =3D {
>>         .atomic_destroy_state =3D drm_atomic_helper_connector_destroy_=
state,
>>  };
>>
>> -static struct drm_connector *
>> -hibmc_connector_init(struct hibmc_drm_private *priv)
>> -{
>> -       struct drm_device *dev =3D priv->dev;
>> -       struct drm_connector *connector;
>> -       int ret;
>> -
>> -       connector =3D devm_kzalloc(dev->dev, sizeof(*connector), GFP_K=
ERNEL);
>> -       if (!connector) {
>> -               DRM_ERROR("failed to alloc memory when init connector\=
n");
>> -               return ERR_PTR(-ENOMEM);
>> -       }
>> -
>> -       ret =3D drm_connector_init(dev, connector,
>> -                                &hibmc_connector_funcs,
>> -                                DRM_MODE_CONNECTOR_VGA);
>> -       if (ret) {
>> -               DRM_ERROR("failed to init connector: %d\n", ret);
>> -               return ERR_PTR(ret);
>> -       }
>> -       drm_connector_helper_add(connector,
>> -                                &hibmc_connector_helper_funcs);
>> -
>> -       return connector;
>> -}
>> -
>>  static void hibmc_encoder_mode_set(struct drm_encoder *encoder,
>>                                    struct drm_display_mode *mode,
>>                                    struct drm_display_mode *adj_mode)
>> @@ -109,13 +83,6 @@ int hibmc_vdac_init(struct hibmc_drm_private *priv=
)
>>         struct drm_connector *connector;
>>         int ret;
>>
>> -       connector =3D hibmc_connector_init(priv);
>> -       if (IS_ERR(connector)) {
>> -               DRM_ERROR("failed to create connector: %ld\n",
>> -                         PTR_ERR(connector));
>> -               return PTR_ERR(connector);
>> -       }
>> -
>>         encoder =3D devm_kzalloc(dev->dev, sizeof(*encoder), GFP_KERNE=
L);
>>         if (!encoder) {
>>                 DRM_ERROR("failed to alloc memory when init encoder\n"=
);
>> @@ -131,6 +98,22 @@ int hibmc_vdac_init(struct hibmc_drm_private *priv=
)
>>         }
>>
>>         drm_encoder_helper_add(encoder, &hibmc_encoder_helper_funcs);
>> +       connector =3D devm_kzalloc(dev->dev, sizeof(*connector), GFP_K=
ERNEL);
>> +       if (!connector) {
>> +               DRM_ERROR("failed to alloc memory when init connector\=
n");
>> +               return -ENOMEM;
>> +       }
>> +
>> +       ret =3D drm_connector_init(dev, connector,
>> +                                &hibmc_connector_funcs,
>> +                                DRM_MODE_CONNECTOR_VGA);
>> +       if (ret) {
>> +               DRM_ERROR("failed to init connector: %d\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       drm_connector_helper_add(connector, &hibmc_connector_helper_fu=
ncs);
>> +       drm_connector_register(connector);
>=20
> You don't need to register a non-hotplug connector as it will be
> registered at drm_dev_register automatically.
>=20
> See function definition:
>=20
>  488 /**
>  489  * drm_connector_register - register a connector
>  490  * @connector: the connector to register
>  491  *
>  492  * Register userspace interfaces for a connector. Only call this
> for connectors
>  493  * which can be hotplugged after drm_dev_register() has been
> called already,
>  494  * e.g. DP MST connectors. All other connectors will be
> registered automatically
>  495  * when calling drm_dev_register().
>  496  *
>  497  * Returns:
>  498  * Zero on success, error code on failure.
>  499  */
>  500 int drm_connector_register(struct drm_connector *connector)
>  501 {
>=20
>=20
> Besides, I don't think this patch cleans much things.

True. Although the auto-kfree of devm_kzalloc() does not work correctly
with DRM and should be replaced.

I'd like to suggest to either allocate the connector as part of struct
hibmc_drm_private, or implement drmm_connector_create() on top of DRM's
new auto-cleanup functionality.

Best regards
Thomas

>=20
> -Xinliang
>=20
>>         drm_connector_attach_encoder(connector, encoder);
>>
>>         return 0;
>> --
>> 2.7.4
>>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>=20

--=20
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany
(HRB 36809, AG N=C3=BCrnberg)
Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer


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