From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
Rob Clark <robdclark@gmail.com>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Sean Paul <sean@poorly.run>,
Abhinav Kumar <quic_abhinavk@quicinc.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Stephen Boyd <swboyd@chromium.org>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
intel-gfx@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
freedreno@lists.freedesktop.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH 2/2] drm/msm/dp: Implement oob_hotplug_event()
Date: Thu, 10 Feb 2022 14:34:30 -0800 [thread overview]
Message-ID: <YgWS9iZ+1uJBd9Lj@ripper> (raw)
In-Reply-To: <YgIecy+W/lGzL6ac@kroah.com>
On Mon 07 Feb 23:40 PST 2022, Greg Kroah-Hartman wrote:
> On Mon, Feb 07, 2022 at 08:43:28PM -0800, Bjorn Andersson wrote:
> > The Qualcomm DisplayPort driver contains traces of the necessary
> > plumbing to hook up USB HPD, in the form of the dp_hpd module and the
> > dp_usbpd_cb struct. Use this as basis for implementing the
> > oob_hotplug_event() callback, by amending the dp_hpd module with the
> > missing logic.
> >
> > Overall the solution is similar to what's done downstream, but upstream
> > all the code to disect the HPD notification lives on the calling side of
> > drm_connector_oob_hotplug_event().
> >
> > drm_connector_oob_hotplug_event() performs the lookup of the
> > drm_connector based on fwnode, hence the need to assign the fwnode in
> > dp_drm_connector_init().
> >
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> > drivers/gpu/drm/msm/dp/dp_display.c | 8 ++++++++
> > drivers/gpu/drm/msm/dp/dp_display.h | 2 ++
> > drivers/gpu/drm/msm/dp/dp_drm.c | 10 ++++++++++
> > drivers/gpu/drm/msm/dp/dp_hpd.c | 19 +++++++++++++++++++
> > drivers/gpu/drm/msm/dp/dp_hpd.h | 4 ++++
> > 5 files changed, 43 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> > index 7cc4d21f2091..124a2f794382 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > @@ -414,6 +414,13 @@ static int dp_display_usbpd_configure_cb(struct device *dev)
> > return dp_display_process_hpd_high(dp);
> > }
> >
> > +void dp_display_oob_hotplug_event(struct msm_dp *dp_display, bool hpd_state)
> > +{
> > + struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
> > +
> > + dp->usbpd->oob_event(dp->usbpd, hpd_state);
> > +}
> > +
> > static int dp_display_usbpd_disconnect_cb(struct device *dev)
> > {
> > struct dp_display_private *dp = dev_get_dp_display_private(dev);
> > @@ -1251,6 +1258,7 @@ static int dp_display_probe(struct platform_device *pdev)
> > dp->pdev = pdev;
> > dp->name = "drm_dp";
> > dp->dp_display.connector_type = desc->connector_type;
> > + dp->dp_display.dev = &pdev->dev;
>
> You did not properly reference count this pointer you just saved. What
> is to keep that pointer from going away without you knowing about it?
>
The "dp" object only lives while &pdev->dev is alive, both logically and
as its devres allocated on &pdev-dev. So for this reference I don't see
that we should refcount it.
> And you already have a pointer to pdev, why save another one here?
>
The Qualcomm DisplayPort driver has per-c-file private context structs
and "dp" is one such object. So I simply can't dereference it and get to
pdev from the other c-file in the same driver...
But I only need it in dp_drm.c to during initialization to get a
reference to the associated fwnode, so it seems that I can rework this
and pass the pointer as a parameter to dp_drm_connector_init().
That looks to be cleaner as well.
Thanks,
Bjorn
next prev parent reply other threads:[~2022-02-10 22:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-08 4:43 [PATCH 1/2] drm: Add HPD state to drm_connector_oob_hotplug_event() Bjorn Andersson
2022-02-08 4:43 ` [PATCH 2/2] drm/msm/dp: Implement oob_hotplug_event() Bjorn Andersson
2022-02-08 7:40 ` Greg Kroah-Hartman
2022-02-10 22:34 ` Bjorn Andersson [this message]
2022-02-08 10:39 ` [PATCH 1/2] drm: Add HPD state to drm_connector_oob_hotplug_event() Greg Kroah-Hartman
2022-02-10 20:56 ` Bjorn Andersson
2022-02-10 21:12 ` Dmitry Baryshkov
2022-02-10 23:24 ` Bjorn Andersson
2022-02-14 17:59 ` Imre Deak
2022-02-14 23:47 ` Bjorn Andersson
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