Date: Wed, 22 Jun 2022 04:47:14 +0200 From: Emmanuel Vadot <manu@bidouilliste.com> To: Chris <bsd-lists@bsdforge.com> Cc: Marek Zarychta <zarychtam@plan-b.pwste.edu.pl>, freebsd-hackers@freebsd.org Subject: Re: Reasons for keeping sc(4) and libvgl ? Message-ID: <20220622044714.c1cf644ae8f34d6ea4b863cb@bidouilliste.com> In-Reply-To: <5812d9bb3a577fdd76fd58d2dd61a9cd@bsdforge.com> References: <20211126160454.3eb827365a02103169ab9adc@bidouilliste.com> <20220621201924.e9b96876c947140ac1f3b7a4@bidouilliste.com> <3d09c86a-9840-f8bf-4725-8098d958a01d@plan-b.pwste.edu.pl> <5812d9bb3a577fdd76fd58d2dd61a9cd@bsdforge.com>
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On Tue, 21 Jun 2022 13:51:17 -0700 Chris <bsd-lists@bsdforge.com> wrote: > On 2022-06-21 11:36, Marek Zarychta wrote: > > W dniu 21.06.2022 o=A020:19, Emmanuel Vadot pisze: > >> Hello, > >>=20 > >> On Fri, 26 Nov 2021 16:04:54 +0100 > >> Emmanuel Vadot <manu@bidouilliste.com> wrote: > >>=20 > >>> Hello all, > >>>=20 > >>> I'm currently re-implementing the framebuffer code in linuxkpi for > >>> drm-kmod and this made me look at sc(4), vt(4) and friends. > >>>=20 > >>> So I looked at what sc could do and vt couldn't and vice-versa. > >>>=20 > >>> What sc(4) can't do : > >>>=20 > >>> - Work with EFI firmware. > >>> - Support UTF-8 > >>> - Maybe other things but everything here is EFI-based so let me kno= w. > >>>=20 > >>> What vt(4) can't do : > >>>=20 > >>> - You can't get the modes or adapter info with vidcontrol. > >>> vidcontrol -i mode is really made for anything vesa based as it > >>> iterates on all the modes and display them if present. > >>> In the modern world (EFI), we don't have that, EFI GOP doesn't > >>> support changing resolution after ExitBootService was called so there > >>> is only one "mode". I could possibly hack some patch so vidcontrol -i > >>> mode/adapter would work and display the current framebuffer info if > >>> people wants (but I honestly doubt that vidcontrol is useful at all in > >>> an EFI world). > >>> - "Blanking" screen doesn't do what you think it does. For some rea= son > >>> in vt(4) we just write black colors on the screen and ignore the blank > >>> mode passed in the ioctl. > >>> Now again, blanking/dpms/blah isn't possible with efi_fb but it m= ake > >>> sense to fix vt(4) and drm-kmod so it calls the drm module blanking > >>> function, I'll work on that next week. > >>> - There is no screensaver, again see notes above for dpms but do > >>> people still use sc(4) just for the screensaver ?? > >>> - Maybe other things, please let me know. > >>>=20 > >>> For libvgl it probably made sense back in the 90s but does it now ?? > >>>=20 > >>> Based on my small list I don't see any good reason to keep sc(4) but > >>> maybe I've missed something bigger so please let me know. > >>>=20 > >>> P.S.: I'm really not interested by people saying stuff like > >>> "I've always used sc(4), it works for me don't touch it" > >>> without some technical argument. > >>>=20 > >>> Cheers, > >>>=20 > >>> -- Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org> > >>>=20 > >> I've put up in phab removing sc(4) from GENERIC and MINIMAL : > >>=20 > >> https://reviews.freebsd.org/D35538 > >> https://reviews.freebsd.org/D35539 > >>=20 > >> If you have any good reason that sc(4) should be included in those > >> kernel config for amd64 (no other arches was touched) please provide > >> some argument on the reviews. > >>=20 > >> Cheers, > >>=20 > > Thanks for heads up. Unfortunately, it will be a great loss. The waste = of=20 > > power > > resources might increase since vt(4) still doesn't support VESA Display= =20 > > Power > > Management Signaling which some of the servers are heavily relying on. = It's=20 > > a step > > backward in terms of green computing and amidst the power crisis, we ar= e=20 > > heading > > in Europe. > My only objection is that I can NOT get textmode or very stable X on any = of=20 > the NVIDIA > cards I use unless I build against sc. Does sc(4) use so much space that= =20 > current kernels > become too big with it's presence? I vote against it's removal. >=20 > Chris I'm sure that other people uses nvidia cards with vt(4), did you opened a PR about this ? --=20 Emmanuel Vadot <manu@bidouilliste.com> <manu@FreeBSD.org>
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