Re: [PATCH rtw-next 3/4] wifi: rtw88: Set AMPDU factor to hardware

[Bitterblue Smith <rtl8821cerfe2@gmail.com>]

On 17/03/2025 05:01, Ping-Ke Shih wrote:
> Bitterblue Smith <rtl8821cerfe2@gmail.com> wrote:
>>
>> Tell the chip the maximum AMPDU size supported by the AP. This greatly
>> improves the TX speed of RTL8814AU in the 2.4 GHz band. Before: ~90
>> Mbps. After: ~300 Mbps.
>>
>> Add this configuration for all the chips, even if it only has an effect
>> on RTL8814AU in my tests. Surely they all need this.
> 
> The hardware default value of REG_AMPDU_MAX_LENGTH is 0xffff (unlimited)
> for most chips. It seems like RTL8812A/RTL8821A are also exceptions, so
> at power on function they do
>     rtw_write32(rtwdev, REG_AMPDU_MAX_LENGTH, 0xffffffff);
> 
> I feel RTL8814A has similar setting, so maybe you can just add similar 
> stuff. 
> 
> By the way, the AMPDU is controlled by TX descriptor basically: 
> 	pkt_info->ampdu_factor = ampdu_factor;
> 	pkt_info->ampdu_density = ampdu_density;
> 	pkt_info->ampdu_en = ampdu_en;
> 
> Since you didn't change this part at all, I still feel setting 
> REG_AMPDU_MAX_LENGTH to 0xffffffff can fix low throughput problem.
> 

I tried 0xffffffff just now and it doesn't work. It's the same with
both of my routers. They advertise a maximum AMPDU size of 64 K.
I can't just set it to 0xffff either, because then the upload speed
in the 5 GHz band suffers a lot. The dual band router advertises a
maximum AMPDU size of 256 K in the 5 GHz band so it gets a value of
0x3ffff.