hw.vga.acpi_ignore_no_vga=1 for installation media

[Daniel Braniss]

> On 17 Mar 2019, at 19:34, Konstantin Belousov <kostikbel at gmail.com> wrote:
> 
> On Sun, Mar 17, 2019 at 10:10:45AM -0600, Warner Losh wrote:
>> I generally like this idea... But two caveats...
>> 
>> First, we'd need to update the docs so that folks doing serial installs can
>> unset it.... Though serial installs are a weird beast....
>> Second, if it's really needed, we should have the installer generate it.
>> alas, only vt can tell us that, but it should be easy to add a sysctl to it
>> that says that it has done video by ignoring the absence of the vga node...
> It is not about VGA node (what is that ?).
> It is about ignoring FACP flag IAPC_BOOT_ARCH={NO_VGA}, and there are
> machines which actually break when trying to access VGA hardware despite
> the flag is set.
> Can anybody provide an example of machine where the flag is set but VGA
> works ?  For me, it is set on headless NUC when there is no monitor
> attached, and then BIOS does not configure framebuffer at all.
> 
> So the proposal is about reversing the set of broken machines, but only
> in installer ?  In other words, if it worked for installer, the installed
> system would be broken (again) ?
> 
>> 
>> Warner
>> 
>> On Sun, Mar 17, 2019 at 6:58 AM Leon Christopher Dietrich <
>> doralitze at chaotikum.org> wrote:
>> 
>>> Sound's like solid idea.
>>> 
>>> A lot of systems out there lack propper ACPI description for VGA and it
>>> would definitly make the installation on such a system much more easy.
>>> 
>>> As far as I can tell it doesn't seam to break other things and even low
>>> power system without VGA (like a pcengines apu2) don't seam to suffer.
> What apu2 reports in FACP flags ?  Do
> 	acpidump -dt | grep IAPC_BOOT_ARCH


mine reports:
	IAPC_BOOT_ARCH=

> 
>>> 
>>> On 17.03.19 13:00, FreeBSD-stable-request at freebsd.org wrote:
>>>> Date: Sun, 17 Mar 2019 02:59:12 +0700
>>>> From: Eugene Grosbein <eugen at grosbein.net>
>>>> To: FreeBSD stable <freebsd-stable at freebsd.org>
>>>> Subject: hw.vga.acpi_ignore_no_vga=1 for installation media
>>>> Message-ID: <912fc95d-5a5e-012b-7385-0f43f50dca65 at grosbein.net>
>>>> Content-Type: text/plain; charset=koi8-r
>>>> 
>>>> Hi!
>>>> 
>>>> Since 11.2-RELESE, default console driver vt(4) checks ACPI table for
>>> presence of VGA in the system.
>>>> It does not initialize console (no input, no output) if ACPI states
>>> there is no VGA adapter.
>>>> 
>>>> There are PRs describing many cases when VGA is present but ACPI lies
>>>> and we have a regression compared with 11.1 and earlier:
>>>> FreeBSD cannot be installed interactively onto such a system, leaving
>>> aside serial console.
>>>> 
>>>> vt(4) has loader knob to restore pre-11.2 behaviour and ignore ACPI:
>>>> 
>>>> hw.vga.acpi_ignore_no_vga=1
>>>> 
>>>> Should we add this unconditionally to the installation media designed
>>> for interactive VGA-based installation?
>>>> 
>>>> 
>>>> ------------------------------
>>>> 
>>> 
>>> 
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