[RFC V2 1/3] drm: implement chaining of drm bridges
Ajay kumar
ajaynumb at gmail.com
Tue May 6 12:51:12 PDT 2014
Rob,
On Tue, May 6, 2014 at 9:42 PM, Rob Clark <robdclark at gmail.com> wrote:
> On Tue, May 6, 2014 at 11:55 AM, Sean Paul <seanpaul at chromium.org> wrote:
>> On Mon, May 5, 2014 at 12:52 PM, Ajay Kumar <ajaykumar.rs at samsung.com> wrote:
>>> As of now, we can have only one bridge hanging off the encoder.
>>> With this patch, we allow multiple bridges to hang onto the same encoder
>>> with the use of a simple next_bridge ptr.
>>>
>>> The drm core calls bridge->funcs for the first bridge which
>>> is attached to it, and its upto the individual bridge drivers
>>> to call bridge->funcs for the next bridge in the chain.
>>>
>>> Signed-off-by: Ajay Kumar <ajaykumar.rs at samsung.com>
>>> ---
>>> drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
>>> include/drm/drm_crtc.h | 2 ++
>>> 2 files changed, 14 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>>> index d8b7099..fe9905f 100644
>>> --- a/drivers/gpu/drm/drm_crtc.c
>>> +++ b/drivers/gpu/drm/drm_crtc.c
>>> @@ -918,8 +918,10 @@ EXPORT_SYMBOL(drm_connector_unplug_all);
>>> * Zero on success, error code on failure.
>>> */
>>> int drm_bridge_init(struct drm_device *dev, struct drm_bridge *bridge,
>>> - const struct drm_bridge_funcs *funcs)
>>> + struct drm_encoder *encoder,
>>> + const struct drm_bridge_funcs *funcs)
>>
>>
>> IMO, we should let whoever is spawning the bridges chain them
>> together, instead of passing encoder in init().
>
> that plus, might be a good time to start adding some static-inline
> helper fxns for fxn ptr calls like we have for drm_panel.. not a big
> deal, but I guess it would be a good time to do it now before we start
> adding chained bridge calls in all the bridges.
Right, I will try to add a few:
-- to update next_bridge ptr and form a chain.
-- to call pre_enable, enable, disable and post_disable for the next
bridge in the list.
Ajay
>
> BR,
> -R
>
>> Sean
>>
>>
>>> {
>>> + struct drm_bridge *temp;
>>> int ret;
>>>
>>> drm_modeset_lock_all(dev);
>>> @@ -931,6 +933,15 @@ int drm_bridge_init(struct drm_device *dev, struct drm_bridge *bridge,
>>> bridge->dev = dev;
>>> bridge->funcs = funcs;
>>>
>>> + if (encoder->bridge) {
>>> + temp = encoder->bridge;
>>> + while (temp->next_bridge)
>>> + temp = temp->next_bridge;
>>> +
>>> + temp->next_bridge = bridge;
>>> + } else
>>> + encoder->bridge = bridge;
>>> +
>>> list_add_tail(&bridge->head, &dev->mode_config.bridge_list);
>>> dev->mode_config.num_bridge++;
>>>
>>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>>> index e55fccb..bb6ed88 100644
>>> --- a/include/drm/drm_crtc.h
>>> +++ b/include/drm/drm_crtc.h
>>> @@ -619,6 +619,7 @@ struct drm_bridge_funcs {
>>> struct drm_bridge {
>>> struct drm_device *dev;
>>> struct list_head head;
>>> + struct drm_bridge *next_bridge;
>>>
>>> struct drm_mode_object base;
>>>
>>> @@ -862,6 +863,7 @@ extern void drm_connector_cleanup(struct drm_connector *connector);
>>> extern void drm_connector_unplug_all(struct drm_device *dev);
>>>
>>> extern int drm_bridge_init(struct drm_device *dev, struct drm_bridge *bridge,
>>> + struct drm_encoder *encoder,
>>> const struct drm_bridge_funcs *funcs);
>>> extern void drm_bridge_cleanup(struct drm_bridge *bridge);
>>>
>>> --
>>> 1.8.1.2
>>>
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