Date: Tue, 26 Jun 2018 10:18:39 -0600 From: Ian Lepore <ian@freebsd.org> To: rgrimes@freebsd.org, Roger Pau Monn? <royger@freebsd.org> Cc: Alexey Dokuchaev <danfe@freebsd.org>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r335629 - in head: share/man/man4 sys/dev/vt/hw/vga Message-ID: <1530029919.24573.74.camel@freebsd.org> In-Reply-To: <201806261555.w5QFtURn003981@pdx.rh.CN85.dnsmgr.net> References: <201806261555.w5QFtURn003981@pdx.rh.CN85.dnsmgr.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 2018-06-26 at 08:55 -0700, Rodney W. Grimes wrote: > > > > On Tue, Jun 26, 2018 at 05:21:27AM +0000, Alexey Dokuchaev wrote: > > > > > > On Mon, Jun 25, 2018 at 08:43:51AM -0700, Rodney W. Grimes wrote: > > > > > > > > > > > > > > New Revision: 335629 > > > > > URL: https://svnweb.freebsd.org/changeset/base/335629 > > > > > > > > > > Log: > > > > > vt: add option to ignore NO_VGA flag in ACPI > > > > > > > > > > To workaround buggy firmware that sets this flag when > > > > > there's actually > > > > > a VGA present. > > > > > > > > > > Reported and tested by: Yasuhiro KIMURA <yasu@utahim > > > > > e.org> > > > > > Sponsored by: Citrix Systems R&D > > > > > Reviewed by: kib > > > > > Differential revision: https://reviews.freebsd.org/D > > > > > 16003 > > > > It is generally best to avoid double negatives, > > > > couldnt this of been better named? (hw.vga.acpi_force_vga) > > > Yes please; I get constantly confused when calculating negatives > > > and > > > often get them wrong. > > This is specifically done to workaround a firmware bug where some > > buggy firmwares set the NO_VGA flag in ACPI. > We are not conflicted about working around the buggy ACPI. > > > > > So the option does > > exactly what the name says, it ignores the NO_VGA flag in ACPI. IMO > > acpi_force_vga is not as descriptive as the current name. > Interestingly that is the text you use to describe it in the man > page, so it seems as if it is good for the description, but not > good for the name of the flag itself? > > .It Va hw.vga.acpi_ignore_no_vga > Set to 1 to force the usage of the VGA driver regardless of whether > ACPI IAPC_BOOT_ARCH signals no VGA support. > Can be used to workaround firmware bugs in the ACPI tables. > > This does not mention the ACPI table entry being over ridden, > if (flags & ACPI_FADT_NO_VGA) > > Further digging I believe you have placed this in the wrong > part of the hierarchy. You put it in hw.vga, and it really > should be in hw.acpi. > Maybe hw.acpi.bootflags.ignore.no_vga. > > Are there any other bootflags we may want to ignore? > > Regards, There is ACPI_FADT_NO_CMOS_RTC, with an associated tunable hw.atrtc.enabled (default is -1), which can be: -1 - enabled unless acpi says ACPI_FADT_NO_CMOS_RTC 0 - unconditionally disabled 1 - unconditionally enabled The idea was that if RTC is provided by EFI runtime services, this flag would indicate that old-school CMOS RTC drivers should not be used. But, predictably, it turns out there are bioses that set this flag even when booting in legacy non-efi mode, leading to a need to ignore the flag and force use of the old driver. -- Ian
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1530029919.24573.74.camel>