From: Hans de Goede <hdegoede@redhat.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Guenter Roeck <linux@roeck-us.net>,
intel-gfx <intel-gfx@lists.freedesktop.org>,
dri-devel@lists.freedesktop.org,
platform-driver-x86@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH 4/9] drm/connector: Add support for out-of-band hotplug notification (v2)
Date: Wed, 5 May 2021 12:42:11 +0200 [thread overview]
Message-ID: <a56b7d60-39a0-8520-8b38-82c0789e4442@redhat.com> (raw)
In-Reply-To: <YJJqeVzS8do3F8wx@kuha.fi.intel.com>
Hi,
On 5/5/21 11:50 AM, Heikki Krogerus wrote:
> On Tue, May 04, 2021 at 05:35:49PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 5/4/21 5:10 PM, Heikki Krogerus wrote:
>>>> +/**
>>>> + * drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
>>>> + * @connector: connector to report the event on
>>>> + * @data: data related to the event
>>>> + *
>>>> + * On some hardware a hotplug event notification may come from outside the display
>>>> + * driver / device. An example of this is some USB Type-C setups where the hardware
>>>> + * muxes the DisplayPort data and aux-lines but does not pass the altmode HPD
>>>> + * status bit to the GPU's DP HPD pin.
>>>> + *
>>>> + * This function can be used to report these out-of-band events after obtaining
>>>> + * a drm_connector reference through calling drm_connector_find_by_fwnode().
>>>> + */
>>>> +void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
>>>> + struct drm_connector_oob_hotplug_event_data *data)
>>>> +{
>>>> + struct drm_connector *connector;
>>>> +
>>>> + connector = drm_connector_find_by_fwnode(connector_fwnode);
>>>> + if (IS_ERR(connector))
>>>> + return;
>>>> +
>>>> + if (connector->funcs->oob_hotplug_event)
>>>> + connector->funcs->oob_hotplug_event(connector, data);
>>>> +
>>>> + drm_connector_put(connector);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_connector_oob_hotplug_event);
>>>
>>> So it does looks like the "data" parameter is not needed at all:
>>
>> Well Imre did indicate that having the number of lanes is useful, so
>> for the next version I'll drop the orientation but I plan to keep
>> the number of lanes if that is ok with you.
>>
>> Not having passing along this info was one of the reasons why my
>> previous attempt at this was nacked, so dropping it all together
>> feels wrong.
>
> If you need to pass any information to the function, then you need to
> pass all the information that we have. Don't start with abstraction.
> First create a dedicated API, and then, only if we really have another
> user for it, we can add an abstraction layer that both users can use.
> All cases are going to be different. We don't know how the abstraction
> / generalisation should look like before we have at least two real
> users (ideally more than two, actually). Right now we can not even say
> for sure that generalising the API is even possible.
>
> I would not make a huge deal out of this unless I wasn't myself being
> told by guys like Greg KH in the past to drop my attempts to
> "generalize" things from the beginning when I only had a single user.
> By doing so you'll not only force all ends, the source of the data
> (the typec drivers in this case) as well as the consumer (i915), to be
> always changed together, it will also confuse things. We are not
> always going to be able to tell the lane count for example like we can
> with USB Type-C, so i915 can't really rely on that information.
>
> Right now we also don't know what exact details i915 (or what ever GPU
> driver) needs. We can only say for sure that some details are going to
> be needed. Trying to guess and cherry-pick the details now does not
> makes sense because of that reason too.
>
> So just make this API USB Type-C DP Alt Mode specific API first, and
> supply it everything we have.
Hmm, ok I'll just drop the data argument all together for now (as you
already suggested); and then we can see what is best once an actual user
for the info shows up.
Regards,
Hans
next prev parent reply other threads:[~2021-05-05 10:42 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-03 15:46 [PATCH 0/9] drm + usb-type-c: Add support for out-of-band hotplug notification (v2) Hans de Goede
2021-05-03 15:46 ` [PATCH 1/9] drm/connector: Give connector sysfs devices there own device_type Hans de Goede
2021-05-03 15:46 ` [PATCH 2/9] drm/connector: Add a fwnode pointer to drm_connector and register with ACPI Hans de Goede
2021-05-03 15:46 ` [PATCH 3/9] drm/connector: Add drm_connector_find_by_fwnode() function (v2) Hans de Goede
[not found] ` <CAHp75Vcv=sUHafBMjV+BMJgmpsXF0iUn5gudb26E2xGapCiMxg@mail.gmail.com>
2021-05-04 11:53 ` Hans de Goede
2021-05-04 12:35 ` Andy Shevchenko
2021-05-03 15:46 ` [PATCH 4/9] drm/connector: Add support for out-of-band hotplug notification (v2) Hans de Goede
2021-05-04 15:10 ` Heikki Krogerus
2021-05-04 15:35 ` Hans de Goede
2021-05-05 9:50 ` Heikki Krogerus
2021-05-05 10:42 ` Hans de Goede [this message]
2021-05-03 15:46 ` [PATCH 5/9] drm/i915: Associate ACPI connector nodes with connector entries Hans de Goede
[not found] ` <CAHp75VcS5nvzBzjbSytqD6qsSURyzdEdmDi934y=5W2SCNyo9A@mail.gmail.com>
2021-05-04 14:56 ` Heikki Krogerus
2021-05-05 9:07 ` Hans de Goede
2021-05-05 9:17 ` Andy Shevchenko
2021-05-05 9:28 ` Hans de Goede
2021-05-05 10:02 ` Andy Shevchenko
2021-05-05 10:30 ` Hans de Goede
2021-05-05 12:55 ` Andy Shevchenko
2021-05-05 10:28 ` Sakari Ailus
2021-05-03 15:46 ` [PATCH 6/9] drm/i915/dp: Add support for out-of-bound hotplug events Hans de Goede
2021-05-03 15:46 ` [PATCH 7/9] usb: typec: altmodes/displayport: Make dp_altmode_notify() more generic Hans de Goede
2021-05-03 15:46 ` [PATCH 8/9] usb: typec: altmodes/displayport: Notify drm subsys of hotplug events Hans de Goede
2021-05-05 10:17 ` Heikki Krogerus
2021-05-05 10:44 ` Hans de Goede
2021-05-03 15:46 ` [PATCH 9/9] platform/x86/intel_cht_int33fe: Correct "displayport" fwnode reference Hans de Goede
2021-05-19 13:37 ` Hans de Goede
2021-05-04 15:22 ` [PATCH 0/9] drm + usb-type-c: Add support for out-of-band hotplug notification (v2) Heikki Krogerus
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