linux-kernel - Re: [PATCH v4 6/7] media: venus: helpers: update NUM

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Date:   Mon, 04 Oct 2021 13:07:22 +0530
From:   dikshita@...eaurora.org
To:     Stanimir Varbanov <stanimir.varbanov@...aro.org>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, vgarodia@...eaurora.org
Subject: Re: [PATCH v4 6/7] media: venus: helpers: update NUM_MBS macro
 calculation

Hi Stan,

On 2021-10-02 03:01, Stanimir Varbanov wrote:
> Hi,
> 
> On 8/10/21 12:47 PM, Dikshita Agarwal wrote:
>> Consider alignment while calculating NUM_MBS.
>> 
>> Co-developed-by: Mansur Alisha Shaik <mansur@...eaurora.org>
>> Signed-off-by: Dikshita Agarwal <dikshita@...eaurora.org>
>> ---
>>  drivers/media/platform/qcom/venus/helpers.c | 13 +++++++------
>>  1 file changed, 7 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/media/platform/qcom/venus/helpers.c 
>> b/drivers/media/platform/qcom/venus/helpers.c
>> index 60a2775..2db33ba 100644
>> --- a/drivers/media/platform/qcom/venus/helpers.c
>> +++ b/drivers/media/platform/qcom/venus/helpers.c
>> @@ -18,8 +18,8 @@
>>  #include "hfi_platform.h"
>>  #include "hfi_parser.h"
>> 
>> -#define NUM_MBS_720P	(((1280 + 15) >> 4) * ((720 + 15) >> 4))
>> -#define NUM_MBS_4K	(((4096 + 15) >> 4) * ((2304 + 15) >> 4))
>> +#define NUM_MBS_720P	(((ALIGN(1280, 16)) >> 4) * ((ALIGN(736, 16)) >> 
>> 4))
>> +#define NUM_MBS_4K	(((ALIGN(4096, 16)) >> 4) * ((ALIGN(2304, 16)) >> 
>> 4))
>> 
>>  struct intbuf {
>>  	struct list_head list;
>> @@ -1098,16 +1098,17 @@ static u32 venus_helper_get_work_mode(struct 
>> venus_inst *inst)
>>  	u32 num_mbs;
>> 
>>  	mode = VIDC_WORK_MODE_2;
>> +
>>  	if (inst->session_type == VIDC_SESSION_TYPE_DEC) {
>> -		num_mbs = (ALIGN(inst->height, 16) * ALIGN(inst->width, 16)) / 256;
>> +		num_mbs = ((ALIGN(inst->height, 16))/16 * (ALIGN(inst->width, 
>> 16)))/16;
> 
> Could you help me understand what is the difference between both
> calculations? IMO this patch should only change NUM_MBS_720P and
> NUM_MBS_4K macros.
> 
We are updating the calculation here to match with the calculation used 
in Macro.
AFAIK, we were seeing a size mismatch for a resolution with the old 
calculation.

>>  		if (inst->hfi_codec == HFI_VIDEO_CODEC_MPEG2 ||
>> -		    inst->pic_struct != HFI_INTERLACE_FRAME_PROGRESSIVE ||
>> -		    num_mbs <= NUM_MBS_720P)
>> +			inst->pic_struct != HFI_INTERLACE_FRAME_PROGRESSIVE ||
>> +			num_mbs <= NUM_MBS_720P)
> 
> This change just makes indentation wrong and also it is not related to
> the patch subject.
I think it can be dropped.
> 
>>  			mode = VIDC_WORK_MODE_1;
>>  	} else {
>>  		num_mbs = (ALIGN(inst->out_height, 16) * ALIGN(inst->out_width, 
>> 16)) / 256;
>>  		if (inst->hfi_codec == HFI_VIDEO_CODEC_VP8 &&
>> -		    num_mbs <= NUM_MBS_4K)
>> +			num_mbs <= NUM_MBS_4K)
> 
> ditto
Same here.
> 
>>  			mode = VIDC_WORK_MODE_1;
>>  	}
>> 
>>