Disappearing WiFi with rt2800pci

I recently did a routine package update on my Fedora 24 laptop. I’ve had the laptop for three years and have been running various Fedorae the whole time, so I didn’t think much of it. So it came as some surprise to me when after rebooting I could no longer connect to my WiFi network. In fact, there was no indication that any wireless networks were even available.

Since the update included a new kernel, I thought that might be the issue. Rebooting into the old kernel seemed to fix it (more on that later!), so I filed a bug, excluded kernel packages from future updates, and moved on.

But a few days later, I rebooted and my WiFi was gone again. The kernel hadn’t updated, so what could it be? I spent a lot of time flailing around until I found a “solution”. A four-year-old forum post said┬ádon’t reboot. Booting from off or suspending and resuming the laptop will cause the wireless to work again.

And it turns out, that “fixed” it for me. A few other posts seemed to suggest power management issues in the rt2800pci driver. I guess that’s what’s going on here, though I can’t figure out why I’m suddenly seeing it after so long. Seems like a weird failure mode for failing hardware.

Here’s what dmesg and the systemd journal reported:

Aug 01 14:54:24 localhost.localdomain kernel: ieee80211 phy0: rt2800_wait_wpdma_ready: Error - WPDMA TX/RX busy [0x00000068]
Aug 01 14:54:24 localhost.localdomain kernel: ieee80211 phy0: rt2800pci_set_device_state: Error - Device failed to enter state 4 (-5)

Hopefully, this post saves someone else a little bit of time in trying to figure out what’s going on.