Re: [PATCH for 4.5] media.h: use hex values for the range offsets, move connectors base up.

[Hans Verkuil <hverkuil@xs4all.nl>]

On 03/03/16 11:12, Laurent Pinchart wrote:
> Hi Hans,
> 
> On Thursday 03 March 2016 11:03:02 Hans Verkuil wrote:
>> On 03/03/16 10:52, Laurent Pinchart wrote:
>>> On Monday 29 February 2016 09:02:47 Hans Verkuil wrote:
>>>> Make the base offset hexadecimal to simplify debugging since the base
>>>> addresses are hex too.
>>>>
>>>> The offsets for connectors is also changed to start after the 'reserved'
>>>> range 0x10000-0x2ffff.
>>>>
>>>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>>>>
>>>> diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
>>>> index 95e126e..79960ae 100644
>>>> --- a/include/uapi/linux/media.h
>>>> +++ b/include/uapi/linux/media.h
>>>> @@ -66,17 +66,17 @@ struct media_device_info {
>>>>
>>>>  /*
>>>>  
>>>>   * DVB entities
>>>>   */
>>>>
>>>> -#define MEDIA_ENT_F_DTV_DEMOD		(MEDIA_ENT_F_BASE + 1)
>>>> -#define MEDIA_ENT_F_TS_DEMUX		(MEDIA_ENT_F_BASE + 2)
>>>> -#define MEDIA_ENT_F_DTV_CA		(MEDIA_ENT_F_BASE + 3)
>>>> -#define MEDIA_ENT_F_DTV_NET_DECAP	(MEDIA_ENT_F_BASE + 4)
>>>> +#define MEDIA_ENT_F_DTV_DEMOD		(MEDIA_ENT_F_BASE + 0x00001)
>>>> +#define MEDIA_ENT_F_TS_DEMUX		(MEDIA_ENT_F_BASE + 0x00002)
>>>> +#define MEDIA_ENT_F_DTV_CA		(MEDIA_ENT_F_BASE + 0x00003)
>>>> +#define MEDIA_ENT_F_DTV_NET_DECAP	(MEDIA_ENT_F_BASE + 0x00004)
>>>>
>>>>  /*
>>>>  
>>>>   * I/O entities
>>>>   */
>>>>
>>>> -#define MEDIA_ENT_F_IO_DTV		(MEDIA_ENT_F_BASE + 1001)
>>>> -#define MEDIA_ENT_F_IO_VBI		(MEDIA_ENT_F_BASE + 1002)
>>>> -#define MEDIA_ENT_F_IO_SWRADIO		(MEDIA_ENT_F_BASE + 1003)
>>>> +#define MEDIA_ENT_F_IO_DTV		(MEDIA_ENT_F_BASE + 0x01001)
>>>> +#define MEDIA_ENT_F_IO_VBI		(MEDIA_ENT_F_BASE + 0x01002)
>>>> +#define MEDIA_ENT_F_IO_SWRADIO		(MEDIA_ENT_F_BASE + 0x01003)
>>>>
>>>>  /*
>>>>  
>>>>   * Analog TV IF-PLL decoders
>>>>
>>>> @@ -84,23 +84,23 @@ struct media_device_info {
>>>>
>>>>   * It is a responsibility of the master/bridge drivers to create links
>>>>   * for MEDIA_ENT_F_IF_VID_DECODER and MEDIA_ENT_F_IF_AUD_DECODER.
>>>>   */
>>>>
>>>> -#define MEDIA_ENT_F_IF_VID_DECODER	(MEDIA_ENT_F_BASE + 2001)
>>>> -#define MEDIA_ENT_F_IF_AUD_DECODER	(MEDIA_ENT_F_BASE + 2002)
>>>> +#define MEDIA_ENT_F_IF_VID_DECODER	(MEDIA_ENT_F_BASE + 0x02001)
>>>> +#define MEDIA_ENT_F_IF_AUD_DECODER	(MEDIA_ENT_F_BASE + 0x02002)
>>>>
>>>>  /*
>>>>  
>>>>   * Audio Entity Functions
>>>>   */
>>>>
>>>> -#define MEDIA_ENT_F_AUDIO_CAPTURE	(MEDIA_ENT_F_BASE + 3000)
>>>> -#define MEDIA_ENT_F_AUDIO_PLAYBACK	(MEDIA_ENT_F_BASE + 3001)
>>>> -#define MEDIA_ENT_F_AUDIO_MIXER		(MEDIA_ENT_F_BASE + 3002)
>>>> +#define MEDIA_ENT_F_AUDIO_CAPTURE	(MEDIA_ENT_F_BASE + 0x03000)
>>>
>>> Why does this one start at 0x*000 while the others start at 0x*0001 ? I
>>> know that the problem predates your patch.
>>
>> I hadn't noticed. It is my personal preference not to start with 0.
>> But it is not needed in this case, at least not today.
>>
>> I think starting with 1 will help if we ever want to do AND operations
>> on the ID. Then it is nice that the lower 16 bits can't be 0 for valid
>> IDs.
> 
> I'm fine starting at 1, would you like to resubmit this patch to change that ?
> 
>>>> +#define MEDIA_ENT_F_AUDIO_PLAYBACK	(MEDIA_ENT_F_BASE + 0x03001)
>>>> +#define MEDIA_ENT_F_AUDIO_MIXER		(MEDIA_ENT_F_BASE + 0x03002)
>>>>
>>>>  /*
>>>>  
>>>>   * Connectors
>>>>   */
>>>>  
>>>>  /* It is a responsibility of the entity drivers to add connectors and
>>>>  links
>>>>
>>>> */ -#define MEDIA_ENT_F_CONN_RF		(MEDIA_ENT_F_BASE + 10001)
>>>> -#define MEDIA_ENT_F_CONN_SVIDEO		(MEDIA_ENT_F_BASE + 10002)
>>>> -#define MEDIA_ENT_F_CONN_COMPOSITE	(MEDIA_ENT_F_BASE + 10003)
>>>> +#define MEDIA_ENT_F_CONN_RF		(MEDIA_ENT_F_BASE + 0x30001)
>>>
>>> Anything wrong with 0x4xxx ?
>>
>> Possibly overkill, but Sakari preferred to make more generous use of the
>> 32 bit space. And since there may potentially be a lot of connector types
>> I thought I gave it plenty of space. Of course, if we ever need that many,
>> then something is seriously wrong...
> 
> And you'd need space *after* the existing connector IDs, not before. Using 
> 0x30000 instead of 0x4000 has the effect of reserving plenty of space for 
> audio functions, not for connectors. I think 0x4000 should be fine.

Huh? Connectors start at 0x30000, audio entities are 0x03000. I think you
got confused by that. Connectors can now go from 0x30000-0xffffffff :-)
Definitely more space than 0x4000-0xffff.

Regards,

	Hans

> 
>>>> +#define MEDIA_ENT_F_CONN_SVIDEO		(MEDIA_ENT_F_BASE + 0x30002)
>>>> +#define MEDIA_ENT_F_CONN_COMPOSITE	(MEDIA_ENT_F_BASE + 0x30003)
>>>>
>>>>  /*
>>>>   * Don't touch on those. The ranges MEDIA_ENT_F_OLD_BASE and
>