Hans de Goede wrote: > On 4/8/22 13:18, Kevin Kofler via devel wrote: >> Still, I remain worried about the details, such as: >> * that, if VESA is needed, the VESA mode has to be configured through the >> kernel CLI, >> * that, as far as I can see, switching to another mode with kernel VESA >> requires a reboot (with different kernel CLI options), > > Both are correct and are indeed somewhat of a downside, although I'm > not sure if Xorg ever automatically uses vesa as fallback of last > resort, or if this needs manual setup.
Hello, I have checked and really Xorg uses VESA as a fallback of last resort without any configuration, at least in Fedora 36 beta. I have booted Fedora 36 LiveCD inside QEMU with the default "-vga std" parameter and in the boot menu selected Troubleshoot -> "Start using basic graphics mode". It used the VESA Xorg driver and the resolution could be switched at runtime. What about virtual machines? * Current versions of QEMU default to "-vga std": "Standard VGA card with Bochs VBE extensions." [1] I have tested Fedora 36 beta and the bochs kernel driver runs fine with Wayland. * Older QEMU versions (I have 4.2.1) with the "-vga vmware" parameter do not support the HW pitchlock and the vmwgfx kernel driver inside the virtual machine errors out with a "Hardware has no pitchlock" message. This works nicely with Xorg and the vmware driver, though. It is also possible that VESA is still used with some cloud providers / etc., at least when the virtual machine does not use UEFI. I have been thinking about writing a KMS version of the uvesafb kernel driver. The uvesafb driver is able to change VESA modes at runtime using a helper program that runs in userspace and executes or emulates VBE (VESA BIOS Extensions) code from the video card BIOS. This will allow Wayland to run on top of VESA/VBE and the user to switch video modes at runtime, from the GUI. This is on my TODO list, but I am not experienced enough with kernel development to do it yet. After all, I am not convinced that there is much benefit in dropping the vesa and fbdev Xorg drivers. There are instances when they could be useful, for example when KMS / other Xorg drivers do not work due to bugs. The user should then be able to get to a workable desktop and at least easily copy logs and submit a bug report. I am not a stakeholder here, though. Greetings, Mateusz [1] https://manpages.ubuntu.com/manpages/jammy/man1/qemu-system.1.html _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
