[PATCH 2/5] drm/amdgpu/vcn:set vcn encode ring priority level

[Christian König]

Am 26.08.21 um 14:31 schrieb Sharma, Shashank:
> On 8/26/2021 5:54 PM, Christian König wrote:
>> Am 26.08.21 um 13:32 schrieb Sharma, Shashank:
>>> Hi Satyajit,
>>>
>>> On 8/26/2021 12:43 PM, Satyajit Sahu wrote:
>>>> There are multiple rings available in VCN encode. Map each ring
>>>> to different priority.
>>>>
>>>> Signed-off-by: Satyajit Sahu <satyajit.sahu at amd.com>
>>>> ---
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 14 ++++++++++++++
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h |  9 +++++++++
>>>>   2 files changed, 23 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c 
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
>>>> index 6780df0fb265..ce40e7a3ce05 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
>>>> @@ -951,3 +951,17 @@ int amdgpu_vcn_enc_ring_test_ib(struct 
>>>> amdgpu_ring *ring, long timeout)
>>>>         return r;
>>>>   }
>>>> +
>>>> +enum vcn_enc_ring_priority amdgpu_vcn_get_enc_ring_prio(int index)
>>>> +{
>>>> +    switch(index) {
>>>> +    case 0:
>>>
>>> As discussed in the previous patches, its far better to have MACROS 
>>> or enums instead of having 0/1/2 cases. As a matter of fact, we can 
>>> always call it RING_0 RING_1 and so on.
>>
>> I strongly disagree. Adding macros or enums just to have names for 
>> the numbered rings doesn't gives you any advantage at all. That's 
>> just extra loc.
>>
>
> Honestly, when I just see case '0', its a magic number for me, and is 
> making code less readable, harder for review, and even harder to 
> debug. RING_0 tells me that we are mapping a ring to a priority, and 
> clarifies the intention.

Well we should probably rename the variable then, e.g. like ring_idx or 
just ring.

A switch on the variable named "ring" with a value of 0 has the same 
meaning than RING_0, it's just not so much code to maintain.

Christian.

>
> - Shashank
>
>> We could use the ring pointers to identify a ring instead, but using 
>> the switch here which is then used inside the init loop is perfectly 
>> fine.
>>
>> Regards,
>> Christian.
>>
>>>
>>>
>>> If this is being done just for the traditional reasons, we can have 
>>> a separate patch to replace it across the driver as well.
>>>
>>> - Shashank
>>>
>>>
>>>> +        return AMDGPU_VCN_ENC_PRIO_NORMAL;
>>>> +    case 1:
>>>> +        return AMDGPU_VCN_ENC_PRIO_HIGH;
>>>> +    case 2:
>>>> +        return AMDGPU_VCN_ENC_PRIO_VERY_HIGH;
>>>> +    default:
>>>> +        return AMDGPU_VCN_ENC_PRIO_NORMAL;
>>>> +    }
>>>> +}
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h 
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>> index d74c62b49795..938ee73dfbfc 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h
>>>> @@ -290,6 +290,13 @@ enum vcn_ring_type {
>>>>       VCN_UNIFIED_RING,
>>>>   };
>>>>   +enum vcn_enc_ring_priority {
>>>> +    AMDGPU_VCN_ENC_PRIO_NORMAL = 1,
>>>> +    AMDGPU_VCN_ENC_PRIO_HIGH,
>>>> +    AMDGPU_VCN_ENC_PRIO_VERY_HIGH,
>>>> +    AMDGPU_VCN_ENC_PRIO_MAX
>>>> +};
>>>> +
>>>>   int amdgpu_vcn_sw_init(struct amdgpu_device *adev);
>>>>   int amdgpu_vcn_sw_fini(struct amdgpu_device *adev);
>>>>   int amdgpu_vcn_suspend(struct amdgpu_device *adev);
>>>> @@ -308,4 +315,6 @@ int amdgpu_vcn_dec_sw_ring_test_ib(struct 
>>>> amdgpu_ring *ring, long timeout);
>>>>   int amdgpu_vcn_enc_ring_test_ring(struct amdgpu_ring *ring);
>>>>   int amdgpu_vcn_enc_ring_test_ib(struct amdgpu_ring *ring, long 
>>>> timeout);
>>>>   +enum vcn_enc_ring_priority amdgpu_vcn_get_enc_ring_prio(int index);
>>>> +
>>>>   #endif
>>>>
>>