svn commit: r312910 - in head: . etc/etc.pc98 etc/rc.d lib/libsysdecode libexec release release/doc release/doc/en_US.ISO8859-1/hardware release/doc/en_US.ISO8859-1/readme release/doc/share/example...

[Warner Losh]

On Wed, Feb 1, 2017 at 10:06 AM, Slawa Olhovchenkov <slw at zxy.spb.ru> wrote:
> On Wed, Feb 01, 2017 at 08:59:40AM -0800, John Baldwin wrote:
>
>> On Wednesday, February 01, 2017 01:35:56 PM Slawa Olhovchenkov wrote:
>> > On Tue, Jan 31, 2017 at 02:46:23PM -0800, John Baldwin wrote:
>> >
>> > > On Tuesday, January 31, 2017 03:33:55 PM Warner Losh wrote:
>> > > > On Tue, Jan 31, 2017 at 3:20 PM, John Baldwin <jhb at freebsd.org> wrote:
>> > > > > On Saturday, January 28, 2017 02:22:15 AM Takahashi Yoshihiro wrote:
>> > > > >> Author: nyan
>> > > > >> Date: Sat Jan 28 02:22:15 2017
>> > > > >> New Revision: 312910
>> > > > >> URL: https://svnweb.freebsd.org/changeset/base/312910
>> > > > >>
>> > > > >> Log:
>> > > > >>   Remove pc98 support completely.
>> > > > >>   I thank all developers and contributors for pc98.
>> > > > >>
>> > > > >>   Relnotes:   yes
>> > > > >
>> > > > > BTW, my impression was that there are some other device drivers
>> > > > > that are effectively PC-98 only (e.g. everything that uses scsi_low.c)
>> > > > > but they might have pccard attachments for use with PC-98 laptops?
>> > > > >
>> > > > > Perhaps Warner might know?
>> > > > >
>> > > > > It seems stg(4) had PCI variants, but nsp(4), ncv(4), and stg(4)
>> > > > > all came from NetBSD/pc98 via PAO.
>> > > >
>> > > > These all work correctly on any PC Card machine. The only reason they
>> > > > came in this way was because these devices were original marketed only
>> > > > in Japan. I've used all these cards with external SCSI drives in the
>> > > > past.
>> > > >
>> > > > As far as I know, only the if_snc driver, which was removed, is truly
>> > > > pc98 specific. It is wired in such a way that cannot be used in ibm-at
>> > > > compatible laptops.  IIRC, it had hard-wired memory decode lines that
>> > > > landed in the middle of the VGA graphics pages or BIOS low memory
>> > > > areas. I have one of these cards still, and it will be detected on my
>> > > > laptops, but can't work due to the required mappings.
>> > > >
>> > > > Now, there's an different question about whether it is time to retire
>> > > > some of the now-ancient SCSI cards from the system, but that's a
>> > > > different kettle of fish that's larger than just nsp, ncv and stg.
>> > >
>> > > Fair enough.  I haven't fully put away my 12 axe and am toying with
>> > > dropping any ISA-only storage and NIC drivers (and perhaps pccard-only
>> > > as well in that case).  Hardware that wants to use ISA/pccard for
>> > > storage is probably happier running 4.x anyway.  One question is if we
>> > > should drop ISA attachments in that case for drivers that support PCI
>> > > and ISA.  However, there's a fair list of ISA-only adapters that would
>> > > be a good place to start anyway.  One concern is to not drop any drivers
>> >
>> > ps/2 keyboard, mouse, touchpads, lm sensors, etc?...
>>
>> Those aren't storage or NICs.  There are many "legacy" device still present
>> in modern systems that we obviously have to support.  However, if you have
>> an ISA Adapter SCSI HBA in an ISA slot, the machine running that is probably
>> happier running 4.x than 12.0.
>
> My be I am missread, I think removed ISA bus and all devices attached
> to ISA bus.

We will never ever ever remove the ISA bus on the i386 or amd64 ports.
That's simply not possible due to the legacy busses and the fact that
many devices are logically attached to the address space used by the
ISA bus even if there aren't physical plastic ISA slots.

Ps/2 keyboards, mice, etc usually also have ACPI attachments. lm
sensors might not, but those are still used and useful.

If you have an ISA system, you are limited to about 16-32MB of RAM.
That's what John is talking about. These systems will barely boot a
modern FreeBSD. However, there are many people that have ISA cards in
a PCI system to do things. Those systems can still run FreeBSD
decently well if they aren't running X11. However, performance of ISA
SCSI and ISA Networking cards for those boxes is horrible and there
are many PCI-based alternatives that should drop in. I have a friend
that has several of these systems he's not going to ever upgrade the
hardware since they work just fine for what he needs. He does want to
run the latest software to pickup security fixes. But AFAIK, none of
these systems is using ISA SCSI. There may be the odd NE-2000
compatible ISA card, but even those have been upgraded a long time ago
when his DSL speeds started to exceed 10Mbps.

John's point is there's little practical value to keeping the old ISA
SCSI cards in the tree. And there's some benefit to removing them
since there are a few CAM features that are used only on one or two of
these systems. ISA Networking cards are limited to 10Mbps (even if
they have PHYs that do 100Mbps) because of the ISA bus. These cards
aren't installed in modern systems, and it is quite doubtful they are
in systems that will be upgraded to 12. And they are untested. Since
there's a non-zero cost in keeping them, there needs to be some
benefit. John is making the case that finding that benefit is
increasingly difficult and we've passed the point where even the
relatively low cost we have to keep the drivers in the system
outweighs the benefit. For many, if not most, of these devices, I'm
inclined to agree with him.

Warner