On 18/03/2025 04:06, Ping-Ke Shih wrote: > Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx> wrote: >> On 17/03/2025 05:01, Ping-Ke Shih wrote: >>> Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx> 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. > > Not sure if 0xffffffff is a special value. Since this is a limit of > AMPDU length, you can set a constant large value such as 0x3ffff you > have tested. Is there special case it can't handle? > > 0x3ffff is not good for the 2.4 GHz band. The upload is only ~90 Mbps with both of the routers I tested. Same with 0x1ffff. Only 0xffff works well for them. 0xffff is too little for the 5 GHz band. The upload speed is ~200 Mbps less than with 0x3ffff. I guess if you really don't want this patch I can hardcode 0xffff and 0x3ffff in rtw8814a_switch_band(). I just don't know if all access points will be happy with that.
