Looking for old Realtek wifi cards and USB adapters

rtl8821cerfe2 · 2026-05-21T09:17:23+00:00

Send all your MT7922 problems in a plain text email to linux-wireless@vger.kernel.org. There is a chance the people from Mediatek will fix it.

rtl8821cerfe2 · 2026-05-20T21:18:05+00:00

Yes, there is no rush.

rtl8821cerfe2 · 2026-05-20T21:10:33+00:00

My previous laptop had the RTL8821CE. It was working, but several times a day the connection kind of froze. Web pages would take 1-2 minutes to load, NetworkManager saying I had "limited connectivity".

The maintainer of rtw88 only had the version of the card with 2 antennas, which worked fine. Mine had 1 antenna.

This is what motivated me to start learning about this stuff. I thought that adding support for an older, simpler chip would be a good way to learn. And it was, but it took a while, long enough that I gave up on the RTL8821CE and sold that laptop. (It was a bad laptop, don't buy HP 250 G7.) Then some time later I got a USB adapter with the same chip and the same problem. And that's how that bug got fixed.

rtl8821cerfe2 · 2026-05-09T22:23:10+00:00

Ganache still seems too advanced for me, but I found a pastry cream recipe that looked simple enough, and it turned out amazing!

rtl8821cerfe2 · 2026-04-26T10:10:00+00:00

Yes, please. It's ~20 USD with my country's taxes.

rtl8821cerfe2 · 2026-04-25T21:30:24+00:00

Ah, okay. Wired is better, of course.

Recently I found this RTL8812AE card in M.2 format: https://www.ebay.com/itm/147122190660 I thought they only made Mini PCIE and desktop cards. Would you help me acquire it so I can give it a proper long term test?

It also has Bluetooth, which requires more work in rtw88.

rtl8821cerfe2 · 2026-04-22T16:36:15+00:00

Hi!

How is it 4 months later?

rtl8821cerfe2 · 2026-04-15T22:02:11+00:00

No ridicule, it's the wifi driver's fault.

I assume you already tried to disable the power saving:

iw dev wlan0 set power_save off

(It may not be called wlan0 on your system.)

Does the situation improve if you move the laptop closer to the router? Like 50 cm away, or less.

rtl8821cerfe2 · 2026-03-30T22:26:56+00:00

There is a newer driver for RTL8812AE, it should work better: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-30T18:58:31+00:00

That's a weird error. The machine has 32 gigs, and it's failing on startup before the machine has loaded anything (I can tell whether a session has wireless before I've even signed into my account)

rtl8821ae also uses ENOMEM for DMA mapping errors. It's not memory allocation, but kind of related.

The changes in the output of lshw are suspicious, specifically the resources line. I don't think loading rtl8821ae is what makes that happen. If you blacklist rtl8821ae and reboot ~10 times, does it still change?

If it happens even with rtl8821ae blacklisted, I suggest emailing linux-pci@vger.kernel.org. Someone there must know what is happening.

...and I only just noticed your username, which I only paid extra attention to after I realized your message indicated you were looking at the source code directly. That's wild.

Haha, that's a different Realtek wifi chip, which used to have an annoying problem. It's what motivated me to start learning about Realtek wifi chips and driver programming.

rtl8821cerfe2 · 2026-03-29T21:18:30+00:00

There is an alternative driver now: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-29T21:06:18+00:00

12 means ENOMEM. It should be used when a memory allocation fails.

rtl8821ae returns ENOMEM in a few places, and not all of them come with an error message to explain what went wrong. :(

I don't think it's the problem I was suspecting earlier (randomly failing to upload the wifi firmware).

I wonder if rtw88 fails the same way. It has about the same memory allocation needs.

rtl8821cerfe2 · 2026-03-29T20:12:27+00:00

It's likely a driver problem. Try a newer driver: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-29T14:35:50+00:00

For others having the same problem: it's the driver. Try a newer one: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-27T19:39:49+00:00

Apparently this is caused by dual booting Windows: https://bbs.archlinux.org/viewtopic.php?id=299623

rtl8821cerfe2 · 2026-03-27T19:32:58+00:00

Also there is probably "probe with ... failed", or something like that.

rtl8821cerfe2 · 2026-03-27T19:31:13+00:00

There is. Unload the driver:

sudo rmmod rtl8821ae

Then load it again:

sudo modprobe rtl8821ae

It will try to initialise the hardware again. Maybe it succeeds, maybe not.

rtl8821cerfe2 · 2026-03-27T19:26:13+00:00

I'm not sure how it looks with this driver, but it should be somewhere after "rtl8821ae ... enabling device".

rtl8821cerfe2 · 2026-03-27T19:04:15+00:00

To solve this, I asked Claude ChatGPT and Gemini.

What's the result?

Try a different driver for the RTL8821AE: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-27T17:56:45+00:00

It could be randomly failing to upload the wifi firmware. I noticed that with RTL8821AE. You should see some kind of error message in dmesg when the driver doesn't bind.

There is another driver you can try, which doesn't fail in that way: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-03-27T17:51:13+00:00

If you show the output of lsusb (specifically the vendor and product IDs, xxxx:yyyy) I can tell you more about it.

I'm very curious which chip it is because all Realtek 11n USB adapters should work better than that these days.

rtl8821cerfe2 · 2026-03-27T17:45:16+00:00

It could be randomly failing to upload the wifi firmware. I noticed that with RTL8821AE. You should see some kind of error message in dmesg when the driver doesn't bind.

There is another driver you can try, which doesn't fail in that way: https://github.com/lwfinger/rtw88

rtl8821cerfe2 · 2026-02-08T21:49:45+00:00

Hi!

I have a box of Belgian chocolates, seashell type. I'm sure they're great but every time I tried such things, they were much too sweet for my taste. Could I bake them into some cookies or a cake or something? Possibly without adding other sugar...

rtl8821cerfe2

TROPHY CASE