On the weekend, I tried Fedora 40 KDE Rawhide (Fedora-KDE-Live-x86_64-Rawhide-20240125.n.0.iso). Kernel 6.8.0-0.rc0.20240112git70d201a40823.5.fc40 was installed, and no newer kernel was offered.
Since kernel 6.7 there is a problem with AMD RX 7x00 XT graphics cards. This problem is still present in this kernel. When the computer is restarted, the monitor switches to standby mode after grub selection and does not wake up on the login screen. However, the OS is already loaded in the background, and you can try to log in blindly. You must shut down the computer completely so that the monitor does not switch back to standby mode when you start the computer again. The monitor will now work until the next system restart.
This issue exists since kernel 6.7. I had the same issue in Nobara 39 with kernel 6.7.0-200 installed. The developer was able to fix this issue by himself. With kernel 6.7.0-204 installed, the issue is fixed in Nobara 39. (See: Discord)
Maybe you already know about this issue? I just want to help to fix this issue before the official (beta-) release of Fedora 40.
Yes. Yesterday I tried latest Rawhide with this kernel and the issue was still there.
I also tried switching kernel from Fedora to CashyOS 6.7.x in Rawhide and the issue still was there. Also, I installed latest openSUSE Tumbleweed with kernel 6.7.x and the issue was there too. So it seems that it isn’t an issue with Fedora kernel only.
Downgraded to kernel-core-6.7.0-0.rc8.20240104gitac865f00af29.64.fc40.x86_64 koji
as described here Downgrading to a previous kernel version and the issue persists
Ergo: most likely kernel not to blame
I’m not replacing distros I just downgrade the kernel
I’m sitting on fc40 for smt like 3 month now and it worked fine
The latest update however left me with a broken GUI
But in my case it doesn’t seem to be the kernel
Pure X11 also seems to work
The rawhide version is currently 40 and will remain so until 40 is branched in the near future. At that time rawhide will become 41 while the branched pre-release version will be 40.
I don’t suggest that you run either rawhide or the branched 40 until much closer to the expected release date of April unless you intentionally want to be using a pure developmental version and can live with any issues that pop up. Only testers should be running that version on a regular basis.
Since you are running 40 (rawhide) you should be reporting problems to the testing mailing list so the developers can become aware of the problems and hopefully fix them as part of the ongoing development cycle.
I have a VM running rawhide and just did an update after about 2 weeks with no updates. First boot gave me a solid black screen but a reboot worked normally with the login screen displayed and functional. The kernel is 6.8.0-0.rc0.20240112git70d201a40823.5.fc40.x86_64 and update was done just a few minutes ago.
Just a note to everyone!
The developers for rawhide probably do not monitor this forum.
If you are using rawhide it is a better choice to report problems on the tester mailing list so the problem is seem by the developers immediately.
Just tried the latest Rawhide ISO (Fedora-KDE-Live-x86_64-Rawhide-20240203.n.0.iso). After installation issue appeared. The monitor went into sleep (Standby) when rebooting the system. But pressing ALT+F3 didn’t do anything. So, my issue isn’t your issue.
As I wrote, there seems to be an issue in connection to kernel 6.7.x (and above) and an AMD RX 7800 XT graphics card. Don’t know if it is the same with RX 7900 XT, but I think so. And it isn’t a specific Fedora issue.
After installing (an OS with) kernel 6.7.x or 6.8.x and rebooting, the monitor goes into sleep mode. There is no way to wake it up again by pressing keys. In the background, it seems that the OS is booting up. So it would be possible to log into the system without seeing anything. Pressing the power button shuts down the computer. Turning it on again and the boot screen is visible and also the login screen appears. Everything is working until the next reboot.
So, the only solution to prevent the monitor going to sleep is shutting down the computer when a reboot is needed.