I have two intel wireless card, one of them is AX200. I didn't know intel disabled all 5g ap mode before buying it. The reason I want to use a wireless card for ap is I want to test how many concurrent connects can a soft ap hold on a x86 platform with better hardware.
I first tested it on win10 with connectify pro and I managed to get it worked on 5g mode. Then I installed Ubuntu20.04 and tested it with hostapd. It also worked with 5g only the channel bandwidth was 20mhz which was so slow, so I replaced it with my the other wireless card. The result was the same. Then I tweaked the configuration file of hostapd and finally got it work with 5g and 80mhz. I tested two wireless cards including the ax200 and the result was great. I even play online games for a few hours connecting to the ap. In the meantime I also rebooted my machine for a few times by the way. And the computer was directly connected to the modem if it matters.
The next day I brought my computer to office trying to figure out how many devices can connect to my pc simultaneously. Then I found out I couldn't enable 5g mode on both intel wireless cards any more.All 5g channel were whether disabled or with no ir, radar detection flag. I even reinstalled ubuntu 20.04 on which they worked before. And this time my pc was connected to a soft router.
Then I searched all over the internet and was so surprised to find out it was never supposed to work as intel disabled all 5g ap channels just like most wireless cards don't support ap mode in 5g.
And now the situation is like what @VRS has mentioned: Intel AX200 ap-mode
I tried everything he said and the result was the same.
I'm not an linux expert and I don't know C and nor do I know if I can bypass the limitation by patching the kernel. I just made a random guess and modified the file: https://github.com/torvalds/linux/blob/master/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c line 315:
if (nvm_flags & NVM_CHANNEL_RADAR)
# flags |= IEEE80211_CHAN_RADAR;
flags |= IEEE80211_CHAN_NO_80MHZ;
and a few lines basically just to replace every IEEE80211_CHAN_RADAR with IEEE80211_CHAN_NO_80MHZ then patched and compiled the kernel and installed it.
And iw list doesn't show the flag no ir, radar detection any more. But hostapd doesn't work and complains Kernel reports: (extension) channels is disabled
Sorry for the pic because it was taken last night and I'm not with my pc now. So photo instead of codes.
Finally, I think changing the flag in the code doesn't help at all only changes the output of the iw list.
I just don't get how these two cards worked in the first place. And why it stopped working. Any ides?
