linux-kernel - Re: [RFC PATCH 3/6] drm/dp: Add is_hpd_asserted() callback to struct drm_dp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <68538a58-54e2-e82e-0789-52eb1cc6b66a@linaro.org>
Date:   Fri, 15 Apr 2022 03:48:07 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Douglas Anderson <dianders@...omium.org>,
        dri-devel@...ts.freedesktop.org
Cc:     Robert Foss <robert.foss@...aro.org>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sankeerth Billakanti <quic_sbillaka@...cinc.com>,
        Philip Chen <philipchen@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Jani Nikula <jani.nikula@...el.com>,
        Kees Cook <keescook@...omium.org>,
        Lyude Paul <lyude@...hat.com>,
        Maxime Ripard <maxime@...no.tech>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 3/6] drm/dp: Add is_hpd_asserted() callback to struct
 drm_dp_aux

On 09/04/2022 05:36, Douglas Anderson wrote:
> Sometimes it's useful for users of the DP AUX bus (like panels) to be
> able to poll HPD. Let's add a callback that allows DP AUX busses
> drivers to provide this.
> 
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

> ---
> 
>   include/drm/dp/drm_dp_helper.h | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
> 
> diff --git a/include/drm/dp/drm_dp_helper.h b/include/drm/dp/drm_dp_helper.h
> index dad1442c91df..a12951319573 100644
> --- a/include/drm/dp/drm_dp_helper.h
> +++ b/include/drm/dp/drm_dp_helper.h
> @@ -2021,6 +2021,20 @@ struct drm_dp_aux {
>   	ssize_t (*transfer)(struct drm_dp_aux *aux,
>   			    struct drm_dp_aux_msg *msg);
>   
> +	/**
> +	 * @is_hpd_asserted: returns true if HPD is asserted
> +	 *
> +	 * This is mainly useful for eDP panels drivers to query whether
> +	 * an eDP panel has finished powering on. This is an optional function.
> +	 *
> +	 * NOTE: this function specifically reports the state of the HPD pin
> +	 * that's associated with the DP AUX channel. This is different from
> +	 * the HPD concept in much of the rest of DRM which is more about
> +	 * physical presence of a display. For eDP, for instance, a display is
> +	 * assumed always present even if the HPD pin is deasserted.
> +	 */
> +	bool (*is_hpd_asserted)(struct drm_dp_aux *aux);
> +
>   	/**
>   	 * @i2c_nack_count: Counts I2C NACKs, used for DP validation.
>   	 */


-- 
With best wishes
Dmitry