From: david on
On Fri, 14 May 2010, Matthew Garrett wrote:

> On Fri, May 14, 2010 at 11:47:43AM -0700, david(a)lang.hm wrote:
>
>> yes, everything has USB ports, so they could use USB keyboards, but it's
>> actually pretty common to still use PS/2 keyboards (and while the systems
>> all support USB, it's not uncommon to have KVM systems, including pretty
>> expensive 'enterprise' KVM systems that still require PS/2 keyboards be
>> used to plug into the KVM, so those are the keyboards that are in the
>> datacenter that someone will grab to plug into a problem machine)
>
> The server hardware I've looked at will all declare the ports regardless
> of whether or not there's something plugged in.

remember that many people use systems in datacenters that are not 'server
hardware'.

when a desktop PC can have 4-6 cores with 8G+ of ram and a couple TB of
storage, a lot of people will end up using those systems for production.

As they grow into bigger companies they will shift to 'server class'
hardware, but startups tend to use whatever they can scrounge (or buy
_really_ cheap)

David Lang
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From: david on
On Fri, 14 May 2010, david(a)lang.hm wrote:

> On Fri, 14 May 2010, Matthew Garrett wrote:
>
>> On Fri, May 14, 2010 at 11:47:43AM -0700, david(a)lang.hm wrote:
>>
>>> yes, everything has USB ports, so they could use USB keyboards, but it's
>>> actually pretty common to still use PS/2 keyboards (and while the systems
>>> all support USB, it's not uncommon to have KVM systems, including pretty
>>> expensive 'enterprise' KVM systems that still require PS/2 keyboards be
>>> used to plug into the KVM, so those are the keyboards that are in the
>>> datacenter that someone will grab to plug into a problem machine)
>>
>> The server hardware I've looked at will all declare the ports regardless
>> of whether or not there's something plugged in.
>
> remember that many people use systems in datacenters that are not 'server
> hardware'.
>
> when a desktop PC can have 4-6 cores with 8G+ of ram and a couple TB of
> storage, a lot of people will end up using those systems for production.
>
> As they grow into bigger companies they will shift to 'server class'
> hardware, but startups tend to use whatever they can scrounge (or buy
> _really_ cheap)

By the way, for what it's worth I think it's a very bad idea to hot-plug
PS/2 keyboards. The hardware may be better nowadays, but back when I was a
PC repair tech I made very good money replacing the fuses on motherboards
that would blow because someone hot-plugged the keyboard.

That said, there are times when it happens, and many people don't see any
problem with it.

David Lang
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From: Matthew Garrett on
On Fri, May 14, 2010 at 11:55:43AM -0700, david(a)lang.hm wrote:

> remember that many people use systems in datacenters that are not 'server
> hardware'.

And if they happen to have one of the (not terribly common) machines
that don't claim device presence when there's no keyboard plugged in,
they can pass the boot option.

--
Matthew Garrett | mjg59(a)srcf.ucam.org
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From: Len Brown on
On Thu, 13 May 2010, Dmitry Torokhov wrote:

> On Thursday 13 May 2010 12:40:43 pm Linus Torvalds wrote:
> > On Thu, 13 May 2010, Dmitry Torokhov wrote:
> > > You don't have anything plugged into the ports though, do you?
> >
> > No. It's a modern machine. But the port is there, and we've been very good
> > at booting up and finding keyboards later (I've done it myself - headless
> > machines that you hotplug a PS/2 keyboard into: it's not necessarily
> > technically something you're supposed to do, but it has worked fine for
> > me).
> >
> > > I wonder what your DSDT looks like.
>
> [... pulling LKML back in...]
>
> Lookie, lookie:
>
> Device (PS2K)
> {
> Name (_HID, EisaId ("PNP0303"))
> Name (_CID, EisaId ("PNP030B"))
> Method (_STA, 0, NotSerialized)
> {
> ShiftLeft (One, 0x0A, Local0)
> If (And (IOST, Local0))
> {
> Return (0x0F)
> }
>
> Return (Zero)
> }
> ...
>
> Device (PS2M)
> {
> Name (_HID, EisaId ("PNP0F03"))
> Name (_CID, EisaId ("PNP0F13"))
> Method (_STA, 0, NotSerialized)
> {
>
> But I guess because there are no devices plugged in ACPI they are "inactive"
> and thus ACPI drop them. I was always wondered by ACPI did that. Len?

I guess only a Windows person could answer this --
since it is really a Windows-ism, rather than something that
makes any sense based on what is in the ACPI spec itself.

cheers,
Len Brown, Intel Open Source Technology Center

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From: Dmitry Torokhov on
On Thu, May 20, 2010 at 12:56:18AM -0400, Len Brown wrote:
> On Thu, 13 May 2010, Dmitry Torokhov wrote:
>
> > On Thursday 13 May 2010 12:40:43 pm Linus Torvalds wrote:
> > > On Thu, 13 May 2010, Dmitry Torokhov wrote:
> > > > You don't have anything plugged into the ports though, do you?
> > >
> > > No. It's a modern machine. But the port is there, and we've been very good
> > > at booting up and finding keyboards later (I've done it myself - headless
> > > machines that you hotplug a PS/2 keyboard into: it's not necessarily
> > > technically something you're supposed to do, but it has worked fine for
> > > me).
> > >
> > > > I wonder what your DSDT looks like.
> >
> > [... pulling LKML back in...]
> >
> > Lookie, lookie:
> >
> > Device (PS2K)
> > {
> > Name (_HID, EisaId ("PNP0303"))
> > Name (_CID, EisaId ("PNP030B"))
> > Method (_STA, 0, NotSerialized)
> > {
> > ShiftLeft (One, 0x0A, Local0)
> > If (And (IOST, Local0))
> > {
> > Return (0x0F)
> > }
> >
> > Return (Zero)
> > }
> > ...
> >
> > Device (PS2M)
> > {
> > Name (_HID, EisaId ("PNP0F03"))
> > Name (_CID, EisaId ("PNP0F13"))
> > Method (_STA, 0, NotSerialized)
> > {
> >
> > But I guess because there are no devices plugged in ACPI they are "inactive"
> > and thus ACPI drop them. I was always wondered by ACPI did that. Len?
>
> I guess only a Windows person could answer this --
> since it is really a Windows-ism, rather than something that
> makes any sense based on what is in the ACPI spec itself.
>

Then we should probably revisit this? I am not saying that we need to
try evaluating more than Windows does but we still should add the
devices into the tree so their presence can be detected.

--
Dmitry
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