Re: [PATCH v3 04/11] media: videobuf2: Stop define VB2_MAX_FRAME as global

[Hsia-Jun Li <Randy.Li@synaptics.com>]

On 7/3/23 18:53, Benjamin Gaignard wrote:
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> Le 03/07/2023 à 10:35, Hsia-Jun Li a écrit :
>>
>> On 7/3/23 16:09, Benjamin Gaignard wrote:
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>>> Le 30/06/2023 à 11:51, Hsia-Jun Li a écrit :
>>>>
>>>> On 6/22/23 21:13, Benjamin Gaignard wrote:
>>>>> CAUTION: Email originated externally, do not click links or open
>>>>> attachments unless you recognize the sender and know the content is
>>>>> safe.
>>>>>
>>>>>
>>>>> After changing bufs arrays to a dynamic allocated array
>>>>> VB2_MAX_FRAME doesn't mean anything for videobuf2 core.
>>>>
>>>> I think make it 64 which is the VB2_MAX_FRAME in Android GKI kernel is
>>>> more reasonable.
>>>>
>>>> It would be hard to iterate the whole array, it would go worse with a
>>>> filter. Such iterate may need to go twice because you mix
>>>> post-processing buffer and decoding buffer(with MV) in the same array.
>>>
>>> Here I don't want to change drivers behavior so I keep the same value.
>>> If it happens that they need more buffers, like for dynamic
>>> resolution change
>>> feature for Verisilicon VP9 decoder, case by case patches will be
>>> needed.
>>>
>> I just don't like the idea that using a variant length array here.
>
> As far I have understand Hans and/or Laurent were happy to use that 
> but I may have misunderstood them.
>
>>
>> And I could explain why you won't need so many buffers for the
>> performance of decoding.
>>
>> VP9 could support 10 reference frames in dpb.
>>
>> Even for those frequent resolution changing test set, it would only
>> happen to two resolutions,
>>
>> 32 would be enough for 20 buffers of two resolution plus golden
>> frames. It also leaves enough slots for re-order latency.
>>
>> If your case had more two resolutions, likes low->medium->high.
>
> VP9 header doesn't tell you that video resolution will change and in 
> which way.
> It cloud be from factor x1/2 to x16 and multiple time so you can use 
> lot of (too much) buffers.

I know VP9 doesn't have sequence header. I think you are talking about 
scaling frame, which should be allocated when it is requested.

And this can't break the max reference capability requirement of VP9.

>
>>
>> I would suggest just skip the medium resolutions, just allocate the
>> lower one first for fast playback then the highest for all the possible
>>
>> medium cases. Reallocation happens frequently would only cause memory
>> fragment, nothing benefits your performance.
>>
>>>
>>>>
>>>>> Remove it from the core definitions but keep it for drivers internal
>>>>> needs.
>>>>>
>>>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>>>> ---
>>>>>   drivers/media/common/videobuf2/videobuf2-core.c | 2 ++
>>>>>   drivers/media/platform/amphion/vdec.c | 1 +
>>>>> .../media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c | 2 ++
>>>>>   drivers/media/platform/qcom/venus/hfi.h | 2 ++
>>>>>   drivers/media/platform/verisilicon/hantro_hw.h | 2 ++
>>>>>   drivers/staging/media/ipu3/ipu3-v4l2.c | 2 ++
>>>>>   include/media/videobuf2-core.h | 1 -
>>>>>   include/media/videobuf2-v4l2.h | 4 ----
>>>>>   8 files changed, 11 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c
>>>>> b/drivers/media/common/videobuf2/videobuf2-core.c
>>>>> index 86e1e926fa45..899783f67580 100644
>>>>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>>>>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>>>>> @@ -31,6 +31,8 @@
>>>>>
>>>>>   #include <trace/events/vb2.h>
>>>>>
>>>>> +#define VB2_MAX_FRAME  32
>>>>> +
>>>>>   static int debug;
>>>>>   module_param(debug, int, 0644);
>>>>>
>>>>> diff --git a/drivers/media/platform/amphion/vdec.c
>>>>> b/drivers/media/platform/amphion/vdec.c
>>>>> index 3fa1a74a2e20..b3219f6d17fa 100644
>>>>> --- a/drivers/media/platform/amphion/vdec.c
>>>>> +++ b/drivers/media/platform/amphion/vdec.c
>>>>> @@ -28,6 +28,7 @@
>>>>>
>>>>>   #define VDEC_MIN_BUFFER_CAP            8
>>>>>   #define VDEC_MIN_BUFFER_OUT            8
>>>>> +#define VB2_MAX_FRAME                  32
>>>>>
>>>>>   struct vdec_fs_info {
>>>>>          char name[8];
>>>>> diff --git
>>>>> a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c
>>>>> b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c
>>>>> index 6532a69f1fa8..a1e0f24bb91c 100644
>>>>> ---
>>>>> a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c
>>>>> +++
>>>>> b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c
>>>>> @@ -16,6 +16,8 @@
>>>>>   #include "../vdec_drv_if.h"
>>>>>   #include "../vdec_vpu_if.h"
>>>>>
>>>>> +#define VB2_MAX_FRAME  32
>>>>> +
>>>>>   /* reset_frame_context defined in VP9 spec */
>>>>>   #define VP9_RESET_FRAME_CONTEXT_NONE0 0
>>>>>   #define VP9_RESET_FRAME_CONTEXT_NONE1 1
>>>>> diff --git a/drivers/media/platform/qcom/venus/hfi.h
>>>>> b/drivers/media/platform/qcom/venus/hfi.h
>>>>> index f25d412d6553..bd5ca5a8b945 100644
>>>>> --- a/drivers/media/platform/qcom/venus/hfi.h
>>>>> +++ b/drivers/media/platform/qcom/venus/hfi.h
>>>>> @@ -10,6 +10,8 @@
>>>>>
>>>>>   #include "hfi_helper.h"
>>>>>
>>>>> +#define VB2_MAX_FRAME                          32
>>>>> +
>>>>>   #define VIDC_SESSION_TYPE_VPE                  0
>>>>>   #define VIDC_SESSION_TYPE_ENC                  1
>>>>>   #define VIDC_SESSION_TYPE_DEC                  2
>>>>> diff --git a/drivers/media/platform/verisilicon/hantro_hw.h
>>>>> b/drivers/media/platform/verisilicon/hantro_hw.h
>>>>> index e83f0c523a30..9e8faf7ba6fb 100644
>>>>> --- a/drivers/media/platform/verisilicon/hantro_hw.h
>>>>> +++ b/drivers/media/platform/verisilicon/hantro_hw.h
>>>>> @@ -15,6 +15,8 @@
>>>>>   #include <media/v4l2-vp9.h>
>>>>>   #include <media/videobuf2-core.h>
>>>>>
>>>>> +#define VB2_MAX_FRAME  32
>>>>> +
>>>>>   #define DEC_8190_ALIGN_MASK    0x07U
>>>>>
>>>>>   #define MB_DIM                 16
>>>>> diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c
>>>>> b/drivers/staging/media/ipu3/ipu3-v4l2.c
>>>>> index e530767e80a5..6627b5c2d4d6 100644
>>>>> --- a/drivers/staging/media/ipu3/ipu3-v4l2.c
>>>>> +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
>>>>> @@ -10,6 +10,8 @@
>>>>>   #include "ipu3.h"
>>>>>   #include "ipu3-dmamap.h"
>>>>>
>>>>> +#define VB2_MAX_FRAME  32
>>>>> +
>>>>>   /******************** v4l2_subdev_ops ********************/
>>>>>
>>>>>   #define IPU3_RUNNING_MODE_VIDEO                0
>>>>> diff --git a/include/media/videobuf2-core.h
>>>>> b/include/media/videobuf2-core.h
>>>>> index 77921cf894ef..080b783d608d 100644
>>>>> --- a/include/media/videobuf2-core.h
>>>>> +++ b/include/media/videobuf2-core.h
>>>>> @@ -20,7 +20,6 @@
>>>>>   #include <media/media-request.h>
>>>>>   #include <media/frame_vector.h>
>>>>>
>>>>> -#define VB2_MAX_FRAME  (32)
>>>>>   #define VB2_MAX_PLANES (8)
>>>>>
>>>>>   /**
>>>>> diff --git a/include/media/videobuf2-v4l2.h
>>>>> b/include/media/videobuf2-v4l2.h
>>>>> index 5a845887850b..88a7a565170e 100644
>>>>> --- a/include/media/videobuf2-v4l2.h
>>>>> +++ b/include/media/videobuf2-v4l2.h
>>>>> @@ -15,10 +15,6 @@
>>>>>   #include <linux/videodev2.h>
>>>>>   #include <media/videobuf2-core.h>
>>>>>
>>>>> -#if VB2_MAX_FRAME != VIDEO_MAX_FRAME
>>>>> -#error VB2_MAX_FRAME != VIDEO_MAX_FRAME
>>>>> -#endif
>>>>> -
>>>>>   #if VB2_MAX_PLANES != VIDEO_MAX_PLANES
>>>>>   #error VB2_MAX_PLANES != VIDEO_MAX_PLANES
>>>>>   #endif
>>>>> -- 
>>>>> 2.39.2
>>>>>
-- 
Hsia-Jun(Randy) Li