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From:   Daniel Vetter <daniel@ffwll.ch>
Date:   Thu, 21 Jan 2021 12:23:07 +0100
Message-ID: <CAKMK7uF=scYJ=gyS=xjYz25mdDzKA0QHSyPndfSBweE7vfDkWQ@mail.gmail.com>
Subject: Re: [PATCH v4] drm: Improve the output_poll_changed description
To:     "ZhiJie.Zhang" <zhangzhijie@loongson.cn>
Cc:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Dave Airlie <airlied@linux.ie>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Jan 21, 2021 at 4:09 AM ZhiJie.Zhang <zhangzhijie@loongson.cn> wrote:
>
> From: zhangzhijie <zhangzhijie@loongson.cn>
>
> this callback was used by drm_kms_helper_hotplug_event()
>
> V2: (Thanks for Daniel's suggestions)
> - remove the FIXME below.since with the drm_client
> - infrastructure and the generic fbdev emulation we've
> - resolved this all very neatly now.
>
> V3: Add comments that This hook is deprecated
> - new implementation methods instead of this hook
>
> Signed-off-by: ZhiJie.Zhang <zhangzhijie@loongson.cn>
> ---
>  include/drm/drm_mode_config.h | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index ab424ddd7665..fbc0da25d7c5 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -103,14 +103,13 @@ struct drm_mode_config_funcs {
>          * Callback used by helpers to inform the driver of output configuration
>          * changes.
>          *
> -        * Drivers implementing fbdev emulation with the helpers can call
> -        * drm_fb_helper_hotplug_changed from this hook to inform the fbdev
> -        * helper of output changes.

Not sure why this isn't clear, but the above is important information
that we should keep. Maybe good to fix up the formatting to make it a
hyperlink, and your addition here is fine too, but the above is the
important part really.
-Daniel

> +        * Drivers implementing fbdev emulation use drm_kms_helper_hotplug_event()
> +        * to call this hook to inform the fbdev helper of output changes.
>          *
> -        * FIXME:
> -        *
> -        * Except that there's no vtable for device-level helper callbacks
> -        * there's no reason this is a core function.
> +        * This hook is deprecated, drivers should instead use
> +        * drm_fbdev_generic_setup() which takes care of any necessary
> +        * hotplug event forwarding already without further involvement by
> +        * the driver.
>          */
>         void (*output_poll_changed)(struct drm_device *dev);
>
> --
> 2.29.2
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch