At Wed, 26 Aug 2026 07:37:40 +0000 (UTC), RVP <rvp%SDF.ORG@localhost> wrote: Subject: Re: genfb(4) vs. screen types and font changes/uses > > It doesn't, and it can't. genfb(4) and vesafb just provide access to a > dumb, linear framebuffer. All resolution changes are are done by the BIOS via > the bootloader. The kernel, ie. genfb(4), can't do this. This is good! (and what I was hoping was happening, based on my initial scan of the code) > > It shouldn't be doing any font switching either. > > Well, I prefer the larger fonts myself, but, if you don't want any font change, > just compile only a single font into the kernel. To each his own for sure, but... The font shouldn't (appear to) change, and the screen shouldn't even be cleared, just because genfb(4) attaches. I'm still not clear for the reason why -- As I said I'm guessing part of it is that once genfb(4) has attached the only way the kernel has to write to the screen is to draw its own character glyphs, though I'm not sure exactly why that should be, especially with UEFI firmware. Nothing should "mess up" the kernel output until after userland starts and some user configuration chooses to use a different font or whatever. The kernel only really needs one font -- the one that matches the standard firmware font, and as I found that's been a standard size for decades. > > I'm betting this part of the reason, if not the whole reason, that > > genfb(4) causes a scrambled mess of bits on the screen on my macbook-air > > when it attaches (thus so far making testing or further development on > > the macbook impossible). > > > > No, that's due to a bootloader bug (which triggers on Macs--which present a > single resolution). Right, the kernel output is messed up from the beginning.... > I have a fix--file a PR soon after I read the UEFI stds > a bit more. This would be awesome! -- Greg A. Woods <gwoods%acm.org@localhost> Kelowna, BC +1 250 762-7675 RoboHack <woods%robohack.ca@localhost> Planix, Inc. <woods%planix.com@localhost> Avoncote Farms <woods%avoncote.ca@localhost>
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