linux-kernel - Re: [PATCH v4 0/4] drm/dp: Introduce wait_hpd

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Message-ID: <CAD=FV=WCCaD-YxhyQeUXe-L06me7XnTRxvsuzjMjWMRYtFxpjw@mail.gmail.com>
Date:   Tue, 21 Jun 2022 09:10:08 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     dri-devel <dri-devel@...ts.freedesktop.org>
Cc:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Robert Foss <robert.foss@...aro.org>,
        Philip Chen <philipchen@...omium.org>,
        Sankeerth Billakanti <quic_sbillaka@...cinc.com>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Imre Deak <imre.deak@...el.com>,
        Jani Nikula <jani.nikula@...el.com>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Jonas Karlman <jonas@...boo.se>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Lyude Paul <lyude@...hat.com>,
        Maxime Ripard <maxime@...no.tech>,
        Neil Armstrong <narmstrong@...libre.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Ville Syrjälä <ville.syrjala@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 0/4] drm/dp: Introduce wait_hpd_asserted() for the DP
 AUX bus

Hi,

On Tue, Jun 14, 2022 at 2:54 PM Douglas Anderson <dianders@...omium.org> wrote:
>
> This is the 2nd four patches from my RFC series ("drm/dp: Improvements
> for DP AUX channel") [1]. I've broken the series in two so we can make
> progress on the two halves separately.
>
> v2 of this series changes to add wait_hpd_asserted() instead of
> is_hpd_asserted(). This allows us to move the extra delay needed for
> ps8640 into the ps8640 driver itself.
>
> The idea for this series came up during the review process of
> Sankeerth's series trying to add eDP for Qualcomm SoCs [2].
>
> This _doesn't_ attempt to fix the Analogix driver. If this works out,
> ideally someone can post a patch up to do that.
>
> [1] https://lore.kernel.org/r/20220409023628.2104952-1-dianders@chromium.org/
> [2] https://lore.kernel.org/r/1648656179-10347-2-git-send-email-quic_sbillaka@quicinc.com/
>
> Changes in v4:
> - Add comment that caller powered up the panel.
> - Comments now explain that we may wait longer due to debouncing.
> - Mention in commit message debouncing vs. powering on timing.
> - Rebased to handle the fact that the stuct moved files.
> - Reorganized logic as per Dmitry's suggestion.
>
> Changes in v3:
> - Don't check "hpd_asserted" boolean when unset.
> - Handle errors from gpiod_get_value_cansleep() properly.
>
> Changes in v2:
> - Change is_hpd_asserted() to wait_hpd_asserted()
>
> Douglas Anderson (4):
>   drm/dp: Add wait_hpd_asserted() callback to struct drm_dp_aux
>   drm/panel-edp: Take advantage of wait_hpd_asserted() in struct
>     drm_dp_aux
>   drm/panel: atna33xc20: Take advantage of wait_hpd_asserted() in struct
>     drm_dp_aux
>   drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in struct
>     drm_dp_aux
>
>  drivers/gpu/drm/bridge/parade-ps8640.c        | 39 +++++++++-----
>  drivers/gpu/drm/panel/panel-edp.c             | 33 ++++++++----
>  .../gpu/drm/panel/panel-samsung-atna33xc20.c  | 51 ++++++++++++++-----
>  include/drm/display/drm_dp_helper.h           | 30 +++++++++++
>  4 files changed, 117 insertions(+), 36 deletions(-)

Pushed to drm-misc-next with Dmitry's reviews.

f5aa7d46b0ee drm/bridge: parade-ps8640: Provide wait_hpd_asserted() in
struct drm_dp_aux
3b5765df375c drm/panel: atna33xc20: Take advantage of
wait_hpd_asserted() in struct drm_dp_aux
2327b13d6c47 drm/panel-edp: Take advantage of wait_hpd_asserted() in
struct drm_dp_aux
841d742f094e drm/dp: Add wait_hpd_asserted() callback to struct drm_dp_aux

-Doug