List of Bug Reports for the mt7921au chipset / mt7921u driver... #107
Comments
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Hi @morrownr I cannot reproduce the mess system log in in 6.0-rc3. Can you please show me full log & reproduce steps(if any special)? Thanks, |
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Hi @deren I will retest on the original system plus two additional systems and report as soon as I can. Regards, Nick |
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Hi @deren I have numbered the bugs so as to make it easier to reference them. The bug in question is now called Bug 2. I have withdrawn Bug 2. After additional testing on different hardware, it appears this bug may be unique to that system so I need to back up and see if I can isolate the cause. Have you been able to duplicate Bug 1? Regards, Nick |
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Hi @morrownr I cannot reproduce Bug2, either. The BT function always working properly, even if plug&play or reload driver several times. But the log is weird to me, it looks like missing fw file on filesystem. Can you please check this problem related to any specific device? Regards, |
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Hi @deren
I have a laptop computer that uses a wifi card based on the mt7921 chipset. Bluetooth works well. However, the subject here is about a usb wifi adapter that uses the mt7921au chipset. I have found no evidence that this adapter supports bluetooth. Is the capability turned off in hardware? I don't know but am trying to find out.
What I posted is not information from a single log. The first section shows the log entries when the most up to date BT firmware is installed. The second section shows the log entries when I delete the BT firmware and reboot. The first section of the log with the firmware installed makes me think the driver is trying to bring BT up but it is unable due to the lack of hardware. Bluetooth support is rare on usb wifi adapters. Could it be that the driver, mt7921u, is making an incorrect assumption that BT hardware is there to use? My mt7921au based usb wifi adapter is showing no sign of support for BT whether the firmware is install or not. This adapter is a Comfast CF-951AX. Regards, Nick |
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Hi @morrownr
Got it. I did not get the point.
What I have is CF-953AX and can verify BT function working well in the card. Regarding the CF-951AX, there are some information about BT function. ( hope that is real :) )
I guess you consider the three lines means the BT function not working properly, right? The log do not show up in my test environment(ubuntu2004+kernel 6.0-rc5 + CF-953AX) and I think this is related to BT protocol usage in your host system. Can you see BT still alive in your system, such as desktop UI? For example, I can see the device is running after CF-953AX plugged.
Regards, |
morrownr
changed the title
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Hi @deren
I consider those 3 lines are possibly going to give a hint as to why BT is not working. And it is not working. I wish I was more familiar with BT but I am not so I am having to go slow with my troubleshooting. I also have a little nano BT adapter with a Braodcome chipset. I plugged it in and BT works with it. Mt test distro is Mint 21 (updated to kernel 6.0 rc3) and a short look at the forums tells me Mint is having problems with BT so I am going to suspend my report pending further investigation. I appreciate your help.
Yes. It shows in the gui applet that supports BT. In fact, with the nano adapter plugged in, both show. The difference is that I can pair with other BT devices with the nano adapter but I can't get anything with the Mediatek based adapter. I'll continue trying to determine the problem. Nick |
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Question: Since you have a Comfast CF-953AX adapter, my question is have you tested AP mode 5 GHz band DFS channel support? I bring this up due to the MANY users that make use of AP mode. Many products also include usb adapters and AP mode is sometimes an important part of the product. I am contacted at times to serve in a consulting roll so I see many use cases that would benefit greatly from this support... and the 5 Realtek drivers I have up here all support this and it works well. There is a gap in capability that needs to be closed and it doesn't seem to be working for me. Thanks, Nick |
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On RasPi4B with Raspbian and kernel 6.0.0-rc7-v8+ (as well as earlier kernels), CF-953AX in AP mode and the latest September 2022 Firmware, I can relatively consistently reproduce firmware hangs by running a speedtest and After the hang, the AP will recover and the following (starting from 4440.067187) is printed in the kernel log. |
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maybe some issues again with usb scatter gather |
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@ayyyuki1 possible. Based on above call trace, mt7921u driver does call a mt76_usb function. I'll try reproducing the issue with |
My opinion is that I would like to see either the default setting for scatter-gather be changed or simple clean the code out of mt76. I have seen the problems that it causes with mt7612u based adapters and I have taken the time to do extensive tests to see if it increases speed in any worthwhile level. My conclusion is that I cannot see any increases in speed. I say dump it from the code. |
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I think the problem with scatter gather was suspected to be a bug in the USB hardware of a Raspberry Pi. |
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With |
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Can the firmware of the VIA chip be upgraded? |
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Yes. |
I'm looking to move this bug report up into message 1 with the other bugs. You mentioned the distro and kernel but did not mention:
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I also want to know if is using an extension cable.
And is it using a powered USB hub.
I had to use a powered USB hub for the keyboard/mouse of my hdmi switch.
Oct. 8, 2022 00:55:53 Nick ***@***.***>:
On RasPi4B with Raspbian and kernel 6.0.0-rc7-v8+[raspberrypi/linux@3fb5ca8] (as well as earlier kernels), CF-953AX in AP mode and the latest September 2022 Firmware, I can relatively consistently reproduce firmware hangs by running a speedtest and *apt upgrade* in parallel on the SC7180 Snapdragon 7c. (Having other devices connected and other traffic patterns sometimes also causes the hang).
@leezu[https://github.com/leezu]
I'm looking to move this bug report up into message 1 with the other bugs. You mentioned the distro and kernel but did not mention:
* > band/channel ?
* > hostapd ? and hostapd.conf
* > WPA3 ?
* > wpa_supplicant version ?
* > 32 bit ?
* > hostapd.log showing anything ?
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band/channel: 36
It uses this extension lead https://smile.amazon.com/gp/product/B082HQXRZ1/ as without extension lead, the CF-953AX covers up the LAN port. |
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I added your firmware hanging issue as Bug 6. Please check it to see if I did a good job. Also, I have been running AP mode 5 GHz over the few days with my RasPi4B. It appears I am seeing the same problem. Every few hours I will lose internet access. It can and usually does recover but it can take a long time. I shut down scatter/gather this morning to see if it helps. We will see. Can I get you to test 2.4 GHz AP mode? Look at Bug 2. I am reporting that 2.4 GHz AP mode is not working. Would like confirmation.
FYI: I think you need 2.10 for WPA3 support. I have a guide to do the upgrade if you want a copy. Nick |
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Regarding bug 6., if I build a vanilla 6.4.rc linux kernel for my raspberry pi 4, I cannot reproduce the issue anymore. |
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Hi @gifter77 Copy all. Will update. |
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it will probably generate useless retrans and it is unlikely to have such a busy environment but:
does it handle well?? How crowded is your 5Ghz? This is my situation. I also live near an heliport and can't really use JP DFS channels. 
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In progress. About one-half of the way complete. I had to have some fun so I ran Ookla from a phone. Given the serious underclock on the RasPi4B and everything that is connected of going, the AP is understandably at max performance conditions. I'm controlling via VNC and the other systems connected to it are still connected. It is stable. The adapter has warmed up a little but nothing to be concerned with. The Edup has vent holes.
Not crowded at all at my current location. I live in a residential neighborhood. The homes all brick and not so close to each other so congestion is minimal on all channels. I use US DFS on my main router for 160 MHz channel width just to have something to test with totally clean air but my test AP in this case is using channel 36. |
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@morrownr I got 4 of the mt7921u/mt7961 that you recommended (fenvi ax1800 non premium). I would like to try "APuP" with these. See https://eko-one-pl.translate.goog/forum/viewtopic.php?pid=304802&_x_tr_sl=pl&_x_tr_tl=en&_x_tr_hl=pl&_x_tr_pto=wapp#p304802 |
I can't say one way or another as I have not tried this. If there is a guide, that leads to the question of what Linux wifi drivers do support it. Let us know what you find out. |
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yeah I'll let you know. I don't consider iw's output very helpful on that front. some have made guides, translating the output, but that was just for ht_capab field. |
I have a PCIe card with that chip and a M.2 card with the mt7925 chip so if you want me to try something for you, write down the commands and I'll give 'um a try. |
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If you want to post an "iw phy" from the mt7925, that might be useful to |
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FYI: I ran ... Here is the link: https://wireless.wiki.kernel.org/en/users/documentation/iw#using_4-address_for_ap_and_client_mode So, you don't check 4addr with The mt7921, mt7922 and mt7925 all report the following: Therefore 4addr should be supported for managed and AP modes. |
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@morrownr is that an iron clad rule though? there are some chips out there which are barely on life support. for example, mwl8k. I tried pi3b with Belkin f9k110x's. ended up not being able to login to the Belkin (it's soft bricked, i reflashed it, it's fine). I will pick back up with an e4200v1 w/ the pi3b in my APuP journey after I flash an e2000 to take the place of the 4200v1 so I wont have a tangible update as soon as i wanted. |
If you are asking if all drivers that are in the kernel support this rule, then my answer is that I doubt it.
When it comes to Linux, I cannot recommend anything Broadcom as their Linux support is not good. Yes, I have a couple of RasPi's but I turn the Broadcom wifi off and use adapters.
The document indicates that is what is intended, not to reflect how it is in all cases... or at least that is my take. Given that the mt76 drivers are as modern and full featured as it gets for Linux wifi, my opinion is that if any Linux drivers support 4addr, then the mt76 drivers would be likely candidates. |
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I have no idea if USB port settings or type of port could be related to the things you gents have been seeing but here is an interesting post on a Debian forum: https://forums.debian.net/viewtopic.php?t=159402 I regularly give advice for users with otherwise unexplainable problems to try a different USB port or check the USB settings in the BIOS. I am aware that there can be a wide array of usb related settings in various BIOS's that are out there and I am aware that USB3 gen 2 can be problematic. Separate subject: After many days of using my mt7921au based adapter (Edup) in AP mode in my Pi4B which is seriously underclocked, I have not seen a single problem. The search continues. |
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@morrownr |
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An interesting data point in this ongoing saga… I installed iperf3 on my desktop (wired gig-E) and laptop (mt7922) and ran a 600-second test of the desktop uploading to the laptop via my router/AP (mt7921u). Averaged 148 Mbit/s and did not hang! (I know the throughput doesn't sound so great, but remember, my router has only USB 2.) And I even performed this test run after having recovered the router from a previous hang without rebooting it. To be sure, I then ran a bitrate-unlimited UDP iperf3 test and hit 876 Mbit/s from the client (desktop), essentially maxing out its gigabit wired Ethernet link, and received 161 Mbit/s (82% packet loss) on the server (laptop), and still the mt7921u in the AP did not hang. So it would seem that my mt7921u AP is perfectly happy to blast packets at max line rate to an mt7922 client, but even a modestly quick download (such as streaming a YouTube video) to my Qualcomm Snapdragon 835-based OnePlus 5T smartphone is often enough to hang the AP, and a max-rate download (such as an Ookla speed test) to it will hang it every time. I might see if I can compile iperf3 for ARM Android and run it on my phone to see if I can reproduce the hangs without involving Ookla. Then maybe I'll put iperf3 on my router/AP box and see if I can still trigger the hangs without involving the Linux software Ethernet bridge. Maybe once this all has been distilled down to a very minimal reproducer, we can hand it to MediaTek, and maybe then they could finally crack this nut. |
Sounds like a plan. I'm going to keep going with testing on my Pi4B for now but within a few days I can probably setup my mini-pc that has totally different hw. The answer is there, we just need to find it. |
@whitslack |
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mt7921 on allwinner can't work I used several development boards including Allwinner h3 and h5, and the results were the same. The kernel is 6.6.52 [ 247.918935] page_pool_create() gave up with errno -22 |
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Hi @ritech
What distro and firmware was in use? |
@ritech: I suspect something may be funky with your kernel configuration or build. Errno 22 is |
same error openwrt/mt76#898 |
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Hi @morrownr. How do I post a feedback? Recently, I saw EDUP AX1672 on your recommended list. It says monitor mode seems to be broken. So I did bought that adapter. I tested the monitor mode, it worked in my case, in a VM (qemu).
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Hi @hyprmann
Right here or you can start a new issue.
Oh no. My wording must be poor. That adapter does monitor mode wonderfully. All of the adapters in the mt7921au section do great with monitor mode as do the adapters in the mt7612u and mt7610u sections. I recently added another document under the Plug and Play List to specifically point Kali users and other monitor mode users to specific adapters. What I was trying to say is that the mt7921u driver currently seems to have a bug in While I have you. Let me recommend that you stop using the Thanks for the info. |
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I see. Now you've mentioned it that Active is a feature within monitor. I thought it;s the same as regular monitor mode. Apologies, my bad. Thanks for the recommendation, I'll check iw out. Thanks again, have a nice day! |
@morrownr, hello there. I got hold of a edup AX3000. But the usb device keep disconnecting. Any suggestion on what might be going wrong? |
It could be a lot of things. Answer some questions: What distro and version are you running on the system with the Edup adapter? Also, kernel version: $ uname -r You are running the Edup in managed mode, correct? What computer hardware are you using with the Edup adapter? Very often, problems can be related to the AP/wifi router. Some details about the AP could help. USB ports can be a problem: You firmware is dated:
You can see how to update it ... |
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@morrownr I am using :
yes I am using it in manager mode:
I have been using another 150 Mbps 2.4GHz wifi adaptor based through the EDIT: After updating the firmware: I still get the same issue. @morrownr can you recommend some good wifi6 pcie cards? |
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Is the HWE kernel for kernel 6.8 available to you yet? If so, it might be a good upgrade. If the new kernel doesn't help... I'll seen similar problems in 2 situations:
Understand that this site is about USB and that is where my experience is so recommending specific cards is not something I am good at. With that said, I have one PCIe card and one M.2 card: The M.2 card uses a mt7925 chip which is WiFi 7. The driver has been in the kernel since 6.7. It performs very well. The PCIe card uses a mt7922 chip which is WiFi 6e with 160 MHz channel width capability. It can do over 1 Gbps easily with a WiFi 6 AP/router as can the M.2 card above. You should be able to get a PCIe card with a mt7925 chip these days. It kinda depends on what you want to spend and what you want to do with it. |
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@morrownr Cause I left you hanging going to give a brief update. I got some of the Linksys Mx4300s when woot was selling their stock of them in drips. So I didn't bother to try MT7921AU WDS configuration. I forgot where exactly I read it, but allegedly APUP isn't as promising as one would expect. according to some people who have tried it, it can work (idk which device they used--probably not mt7921u), but the delivered bandwidth was LESS THAN with standard WDS. I don't recall if they compared speeds for apup vs mesh, but apup vs wds, wds was according to these 1-2 people (a statistically significant anecdote this isn't) the clear winner. The difference in bandwidth was fairly big, iirc I'm still learning how to leverage the MX4300. I need to learn how to do dynamic link aggregation with 1x wan and 1x lan to both ports of my gateway device. Until I do that, I can't achieve full bandwidth. Maybe more straightforward to do on a ddwrt box? I have read some, to that effect. Going past that I want to learn the best ways to setup 802.11s or any better form of mesh topology be it software based (batman or oslr etc) or standard 802.11s. Right now I'm using normal WDS to link some of these. The speeds are better then I was getting with ea3500 for linking buildings, and there's no longer packet loss. The packet loss element may be due to previous AP not supporting LDPC over 2.4. So the 2x2 with LDPC ax setup is running better than the 3x3 n without it probably not shocking. |
I picked a MX4300 up also. I think it was for 20 usd and put it aside until such time as OpenWRT support is in place. It might be good for testing or as a backup. Do we have support yet along with instructions?
I have never spent any serious time with mesh because I have really never needed it... or at least I have not thought I needed it. It would be good to get my MX4300 out of the box sometime soon and give it a ride. You are welcome start a new issue to discuss installing OpenWRT on the Linksys MX4300 if you want. I am aware of the Issue in the OpenWRT Dev forum but it wanders all over the place and I seem to stay busy on other things. It would be good to have someone to talk to about setting up the MX4300. |
and others
This issue is for maintaining a list of problematic issues that need work. This list will be maintained and updated in this first post by @morrownr . Please add posts to this issue as you have updated information for the existing BUGs in the list or if you have information about a new BUG. Thank you.
Dear Mediatek devs... help is appreciated.
Bug: (2024-04-18) See: #392 . WDS/4addr not supported in AP mode. First reported with Alfa AXML adapter that uses the mt7921au chipset and mt7921u driver). The OP is unable to use WDS/4addr in AP mode.
Status: Open
Info: It was reported that this capability does work with an adapter that uses the mt7612u chipset/driver.
Bug: (2024-03-26) See: #378 Wifi adapter not showing up. First reported with Alfa AXML adapter that uses the mt7921au chipset and mt7921u driver). The adapter is non-functional until using the workaround below.
Status: Open
Workaround: the workaround is to run
modprobe -r btusbfirst, then plug in the usb wifi adapter.More input is needed. Is this a problem with btusb?
Update: When testing the Alfa AXML with Ubuntu 24.10, the system locks up. Things seem to be getting worse instead of better.
Bug: (2023-12-22) Linux distros are detecting Bluetooth capability in Alfa AXML. Alfa AXM and Confast 953 mt7921au based adapters but none of the adapters on the market have Bluetooth turned on so it won't work. Linux should not be detecting Bluetooth capability when it is actually not available.
Update: Evidently some Alfa AXML and AXM adapter do have bluetooth support turned on. I wish they would not do that but it is what it is. This problem is getting worse.
Status: Open and ongoing
Here is a link to a location where you can get a copy of the Intel White Paper that explains the details of why USB3 capable WiFi adapters should not have Bluetooth capability turned on:
https://www.usb.org/document-library/usb-30-radio-frequency-interference-impact-24-ghz-wireless-devices
USB3 WiFi adapters should not have Bluetooth turned on as the USB3 will cause interference with Bluetooth. If makers decide they really want Bluetooth capability in an adapter then they need to limit wifi to USB2 capability. All adapters with the mt7921au chipset that I am aware of have Bluetooth turned off so WiFi can operate in USB3 mode. However, there is a bug in that Bluetooth capability is still being detected by Linux distros and the driver/firmware is loading. Systems act like Bluetooth is available but when you try to use the Bluetooth, it won't work. It is not clear to me how this can be fixed but it really does need to be fixed.
This is not a problem with PCIe cards. I have a mt7922 based PCIe card. Wifi and Bluetooth work well together because wifi uses the PCIe bus and not USB. Please understand that issue in this bug is not exclusive to this chipset. This is an issue will all USB WiFi adapters. The adapters that have USB wifi capability and BT capabilities over the years have limited USB to USB2 to avoid the problem of interference.
Bug: (2023-12-07) Active monitor mode seems to be broken.
Status: open
Reporter: @ZerBea
Link: openwrt/mt76#839
Problem: Using Active Monitor mode breaks the driver
Driver reports that active monitor mode is possible:
$ iw list | grep active
Device supports active monitor (which will ACK incoming frames)
But if hcxdumptool set active monitor mode, it stops working.
If active monitor mode is disabled, everything's fine
0 ERROR(s) during runtime
638 Packet(s) captured by kernel
0 Packet(s) dropped by kernel
1 SHB written to pcapng dumpfile
1 IDB written to pcapng dumpfile
1 ECB written to pcapng dumpfile
83 EPB written to pcapng dumpfile
exit on sigterm
I don't think the problem is related to hcxdumptool, because it can be reproduced with iw, ip link and tshark, too:
$ sudo ip link set wlp22s0f0u4i3 down
$ sudo iw dev wlp22s0f0u4i3 set type monitor
$ sudo ip link set wlp22s0f0u4i3 up
$ tsahrk -i wlp22s0f0u4i3
22 packets captured
$ sudo ip link set wlp22s0f0u4i3 down
$ sudo iw dev wlp22s0f0u4i3 set monitor active
$ sudo ip link set wlp22s0f0u4i3 up
$ tshark -i wlp22s0f0u4i3
Capturing on 'wlp22s0f0u4i3'
^C
0 packets captured
Background:
Running active monitor mode, the device ACK incoming frames addressed to the virtual MAC of the device.
This feature is really useful to perform PMKID attacks.
At the moment, active monitor mode is working on:
mt76x0u
mt76x2u
It is not working on:
mt7601u
mt7921u
I see two options:
active monitor mode should be fixed, or
active monitor mode capability should not be reported by the driver
mt7601u
$ iw list | grep active
Device supports active monitor (which will ACK incoming frames)
mt7921u
$ iw list | grep active
Device supports active monitor (which will ACK incoming frames)
Bug: LED does not function in several of the usb wifi adapters that use the mt7921au chipset.
Status: open, it appears that LED support was never added to the driver.
Reported by @morrownr
Confirmed by numerous users.
Bug: AP Mode DFS (5 GHz) support is non-functional
Status: open
Reported by @morrownr
Confirmed by numerous users.
This is really a serious omission in that in many places in the world there are limited non-DFS channels available leading to high levels of congestion.
Dear Mediatek, does your usb chipset competitor support DFS channels in AP Mode? Yes they do. See: out-of-kernel drivers for rtl8852cu, rtl8812au, rtl8811au, rtl8812bu and rtl8811cu. You need to think about this. Sincerely.
Bug: txpower reading is showing as unusually low as in 3 dBm using
iw.Status: open
Reported by several individuals.
This reading is wrong. This really needs to be fixed. It is better to output nothing as opposed to something that wrong.
Bug: (feature request) mt7921u driver does not support 2 interfaces of AP mode on one adapter
Status: open
Reported by @whitslack
mt7921u driver does not support 2 instances of AP mode whereas this was common on some drivers for older adapters.
Bug: connection is dropped and the only way to correct the situation is to reboot (AP mode)
Status: open
Testing to see if SG helps performance:
scatter-gather test with mt7921au based adapter
Issue: connection drops and the only resolution is to reboot the system.
Raspberry Pi 4B
RasPiOS 2023-05-03
I changed the modulate parameter and rebooted between each test so as to alternate on and off.
iperf3 -c 192.168.1.1 -t 300
scatter-gather off (disable_usb_sg=1)
scatter-gather on (disable_usb_sg=0)
Observation: So much for needing to average the results. I was careful
to check that sg was on or off. I have no explanation for how the results
could be so close. I see no evidence that sg is providing any performance
increase.
Previous to this testing session, I have been able to see the issue of
the connection being dropped and only a reboot will connect the
situation. It happened twice a few days ago while testing with sg on.
There is a history of this with mt7612u adapters. I have yet to duplicate
the issue with sg off.
Conclusion: Further testing on different platforms is needed. I will test
x86_64 next. Given the history of sg causing problems such as connections
dropping that can only be corrected with a reboot, it may be better for the
default to be disable_usb_sg=1 with a follow up to determine what the
problem is.
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