On 11/10/2016 04:53 PM, Laurent Pinchart wrote:
> Hi Shuah,
>
> On Tuesday 08 Nov 2016 12:20:29 Shuah Khan wrote:
>> On Tue, Nov 8, 2016 at 6:55 AM, Sakari Ailus wrote:
>>> From: Sakari Ailus <sakari.ailus@xxxxxx>
>>>
>>> Allow allocating the media device dynamically. As the struct media_device
>>> embeds struct media_devnode, the lifetime of that object is that same than
>>> that of the media_device.
>>>
>>> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
>>> ---
>>>
>>> drivers/media/media-device.c | 15 +++++++++++++++
>>> include/media/media-device.h | 13 +++++++++++++
>>> 2 files changed, 28 insertions(+)
>>>
>>> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
>>> index a31329d..496195e 100644
>>> --- a/drivers/media/media-device.c
>>> +++ b/drivers/media/media-device.c
>>> @@ -684,6 +684,21 @@ void media_device_init(struct media_device *mdev)
>>> }
>>> EXPORT_SYMBOL_GPL(media_device_init);
>>>
>>> +struct media_device *media_device_alloc(struct device *dev)
>>> +{
>>> + struct media_device *mdev;
>>> +
>>> + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
>>> + if (!mdev)
>>> + return NULL;
>>> +
>>> + mdev->dev = dev;
>>> + media_device_init(mdev);
>>> +
>>> + return mdev;
>>> +}
>>> +EXPORT_SYMBOL_GPL(media_device_alloc);
>>> +
>>
>> One problem with this allocation is, this media device can't be shared
>> across drivers. For au0828 and snd-usb-audio should be able to share the
>> media_device. That is what the Media Allocator API patch series does.
>
> No disagreement here, Sakari's patches don't address the issues that the media
> allocator API fixes. The media allocator API, when ready, should replace (or
> at least complement, if we decide to keep a simpler API for drivers that don't
> need to share a media device, but I have no opinion on this at this time) this
> allocation function.
Media Device Allocator API is ready and reviewed. au0828 uses it as the first
driver using it. I will be sending out snd-usb-audio patch soon that makes use
of the shared media device.
thanks,
-- Shuah
>
>> This a quick review and I will review the patch series and get back to
>> you.
>>
>>> void media_device_cleanup(struct media_device *mdev)
>>> {
>>> ida_destroy(&mdev->entity_internal_idx);
>>> diff --git a/include/media/media-device.h b/include/media/media-device.h
>>> index 96de915..c9b5798 100644
>>> --- a/include/media/media-device.h
>>> +++ b/include/media/media-device.h
>>> @@ -207,6 +207,15 @@ static inline __must_check int
>>> media_entity_enum_init(
>>> void media_device_init(struct media_device *mdev);
>>>
>>> /**
>>> + * media_device_alloc() - Allocate and initialise a media device
>>> + *
>>> + * @dev: The associated struct device pointer
>>> + *
>>> + * Allocate and initialise a media device. Returns a media device.
>>> + */
>>> +struct media_device *media_device_alloc(struct device *dev);
>>> +
>>> +/**
>>> * media_device_cleanup() - Cleanups a media device element
>>> *
>>> * @mdev: pointer to struct &media_device
>>> @@ -451,6 +460,10 @@ void __media_device_usb_init(struct media_device
>>> *mdev,
>>> const char *driver_name);
>>> #else
>>> +static inline struct media_device *media_device_alloc(struct device *dev)
>>> +{
>>> + return NULL;
>>> +}
>>> static inline int media_device_register(struct media_device *mdev)
>>> {
>>> return 0;
>
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