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Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?

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Old 12-22-2005, 08:31 PM   #1
slinky2004
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do i need ISA bus support?


i'm compiling a new kernel, i've just gotten to the bus options section and i don't know if i need ISA bus support. lspci shows an ISA bridge:
Quote:
00:1f.0 ISA bridge: Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge (rev 03)
but i dunno if that means I have an isa bus, because why would lspci find the ISA bus? its a totally different bus, isnt it? i think my touchpad may be on the isa bus also:
Quote:
input: AT Translated Set 2 keyboard on isa0060/serio0
input: PS/2 Mouse on isa0060/serio1
input: AlpsPS/2 ALPS GlidePoint on isa0060/serio1
. A while ago i tried using lm-sensors and that sensors-detect script found some stuff when it scanned the isa bus, not all of it was sensors, but there were devices on some of the offsets it scanned, if i remember correctly.

what i dont get is, my last kernel didnt have any isa bus support and my mouse and keyboard still work fine, wouldnt they stop working if they were on the ISA bus and i didnt have the driver for it?
 
Old 12-22-2005, 09:27 PM   #2
Matir
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Your mouse and keyboard are not on a real ISA bus. My computer shows the same status, and I have no ISA bus support. That being said, even if your computer has no ISA slots, some sensors may be attached to an ISA chipset. ISA is slow, but plenty fast for sensors.
 
Old 12-22-2005, 10:59 PM   #3
slinky2004
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why does it say isa0060/serio1 for my input devices tho? they dont show up in lspci, so i figured they were on the isa bus.

why does the isa bus show up as a pci device? how can a bus be a pci device?

another quick question: why do i have two lines for my touchpad?
Quote:
input: PS/2 Mouse on isa0060/serio1
input: AlpsPS/2 ALPS GlidePoint on isa0060/serio1
i only have one mouse device attatched, the ALPS touchpad. i'm assuming those lines are initializing some mouse drivers, but shouldnt it use either the ps/2 mouse driver or the touchpad driver, not both? where is this isa0060/serio device anyway? i cant find it in /dev.

Last edited by slinky2004; 12-22-2005 at 11:08 PM.
 
Old 12-23-2005, 08:42 AM   #4
Matir
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isa0060/serio1 is not a device. It's a port. It's the internal connection for the touchpad on your notebook. Additionally, does your notebook have a PS/2 port? It may be recognizing that, despite no connected device.

The ISA bus shows up because it is an ISA Bridge: that is, anything on the ISA bus will be passed to the PCI bus before being sent to the processor.
 
Old 12-23-2005, 01:32 PM   #5
slinky2004
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i dont have a ps/2 port on here, so i dunno what that extra line is for. thanks for the help
 
Old 12-23-2005, 02:25 PM   #6
Matir
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No problem. In conclusion, I'd say that you should be fine without ISA bus support. If you later discover some hardware not showing up, you can always switch it back on. Until I installed lm-sensors on my desktop, I had no ISA bus support with no problems at all.
 
Old 11-21-2007, 10:26 AM   #7
HowDoIProgramIt
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Quote:
Originally Posted by slinky2004 View Post
i dont have a ps/2 port on here, so i dunno what that extra line is for. thanks for the help
It could be that your motherboard has PS/2 mouse support circuitry but the motherboard mfgr sold the cables to support it separately. I've seen quite a few motherboards that have support for IR, IEEE-1394, an additional serial port, etc., but where the connector & cable set allowing you to use those features is "sold separately" (they never do seem to give much info as to how one might go about buying them, either).

That can work to your advantage; if Linux detects that you have hardware support for something, it'll often be able to utilize that something. Often without any additional drivers, etc. One machine I bought pre-built ended up having on-board SATA support, which Linux detected and used without my having to do anything except add a SATA drive to the machine; Windows needed to have a driver - actually, several - installed in order to use the same controlller.

Quote:
Originally Posted by Matir
Your mouse and keyboard are not on a real ISA bus. My computer shows the same status, and I have no ISA bus support. That being said, even if your computer has no ISA slots, some sensors may be attached to an ISA chipset. ...
It's a real ISA bus; I think you mean it's not accessible from the standpoint of not being able to plug a card onto it, etc.

The ISA bus bridge (and a number of other things in a modern PC) is "a compatibility thing"; in the very beginning, there was an 8042 keyboard controller chip, an 8259 PIC, an 8254 timer, etc. The 8259 PIC evolved quickly into two daisy-chained 8259s which meant 15 interrupts (with 2 & 10 "shared"). Which wouldn't be nearly enough for a modern computer; most anything you buy today has a lot more than 15 interrups; and, has hardware supports for interrupt sharing, etc. As with most other discrete components, the 8042 & the 8254 chips disappeared, too; by and large, discrete components disappeared when manufacturing / fabrication technology improved to the point that the same functionality could be provided by much-larger-scale-integration, multi-function chips.

The replacements, though, had to react the same way that the chips they replaced did. Especially early-on, when RAM was limited (and expensive), a number of creative programming techniques were employed to make the PC do things it otherwise wouldn't have been able to (there was a lot of creativity in hardware, too; one of the problems with addressing memory above the 1Mb mark was that address line A20 was originally controlled by the keyboard controller and couldn't function near fast enough to allow extended memory to function in a timely manner).

If they hadn't functioned in a manner virtually identical to those parts which they replaced, too many things (both software and hardware) would have stopped working, necessitating either a complete redesign of the PC (of the time) or the continued use of discrete components - which were more expensive, consumed more power, took up more space, etc.

I know that's a bit long; hope it isn't too boring. It sounded like slinky2004 was trying to figure out why some of what appears inside modern computers, still appears inside modern computers. There are a number of things that really don't make much sense at all unless you know the history behind them.

Hope that helps

- Larry
 
  


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