"Arnd Bergmann" <arnd@xxxxxxxx> writes: Hello Arnd, > On Wed, Feb 26, 2025, at 09:16, Thomas Zimmermann wrote: >> Am 26.02.25 um 08:55 schrieb Arnd Bergmann: >> Here's another general question. vgacon and fbcon only seem usable with >> CONFIG_VT=y. Wouldn't it make sense to have them depend on CONFIG_VT=y? >> dummycon could then be implemented as part of the vt code, maybe even >> become a vt-internal thing. The console code is complex, so I'm probably >> missing something here? > > I think in theory one may have a system use fbcon purely to get the > boot logo, but not actually support VT. I had also assumed there might > be a way to use fbcon as the console (i.e. printk) but not register > the tty, but it looks like the console code still requires vt. > > After I looked at the vt and conswitchp code some more, I wonder > if we could go the other way and instead of integrating it more > make the conswitchp logic optional: most of the complexity here > deals with switching between text console and fbcon dynamically, > but having any text console support is getting very rare (vga > on alpha/mips/x86-32, newport on mips-ip22, sti on parisc). > > If we do this, the conswitchp code could be merged with dummycon This sounds like a much better approach indeed. > in drivers/video/console, with the simpler alternative just > calling into fbcon functions. I'm not sure if we can already drop > vgacon from normal x86-64 distro configs, i.e. if there are cases > that are not already covered by any of efi-earlycon, efifb, > vga16fb, vesafb/uvesafb or a PCI DRM driver. > I believe vgacon is still useful for x86 with legacy BIOS, because vesafb (and simpledrm) only works if the user defines a mode using the vga= kernel cmdline parameter. > Arnd > -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
