[RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Nick Andrew]

I'm doing a couple of cleanups to Documentation/i386/IO-APIC.txt
and I have a problem with this line, which is supposed to compute
a sample pirq= kernel parameter:

   echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'

The 'scanpci' command used to be part of xutils and/or XFree86.
Xorg implements "Xorg -scanpci" but the output is different and it won't
run while X is running.

Firstly I propose using the $( ) construct rather than backticks, since
it is easier to read:

   echo -n pirq=; echo $( scanpci | grep T_L | cut -c56- ) | sed 's/ /,/g'

Inside the backtics, instead of scanpci, I could do:

   lspci -v | grep IRQ | sed -e 's/.* IRQ \(\w\+\)/\1/'

Is this an acceptable substitution?

Nick.
-- 
PGP Key ID = 0x418487E7                      http://www.nick-andrew.net/
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Re: [RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Ingo Molnar]

* Nick Andrew <nick@nick-andrew.net> wrote:

> I'm doing a couple of cleanups to Documentation/i386/IO-APIC.txt
> and I have a problem with this line, which is supposed to compute
> a sample pirq= kernel parameter:
> 
>    echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g'
> 
> The 'scanpci' command used to be part of xutils and/or XFree86.
> Xorg implements "Xorg -scanpci" but the output is different and it won't
> run while X is running.
> 
> Firstly I propose using the $( ) construct rather than backticks, since
> it is easier to read:
> 
>    echo -n pirq=; echo $( scanpci | grep T_L | cut -c56- ) | sed 's/ /,/g'
> 
> Inside the backtics, instead of scanpci, I could do:
> 
>    lspci -v | grep IRQ | sed -e 's/.* IRQ \(\w\+\)/\1/'
> 
> Is this an acceptable substitution?

yeah, i guess so.

Btw., that's rather arcane text - do people still have to use pirq= boot 
lines to get their boxes to boot?

	Ingo

Re: [RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Nick Andrew]

On Sun, Apr 13, 2008 at 10:45:36AM +0200, Ingo Molnar wrote:
> 
> * Nick Andrew <nick@nick-andrew.net> wrote:
> >    echo -n pirq=; echo $( scanpci | grep T_L | cut -c56- ) | sed 's/ /,/g'
> > 
> > Inside the backtics, instead of scanpci, I could do:
> > 
> >    lspci -v | grep IRQ | sed -e 's/.* IRQ \(\w\+\)/\1/'
> > 
> > Is this an acceptable substitution?
> 
> yeah, i guess so.
> 
> Btw., that's rather arcane text - do people still have to use pirq= boot 
> lines to get their boxes to boot?

I wouldn't know that, but I still have to use 'noapic' to get my AMD box
to boot :-(

Nick.
-- 
PGP Key ID = 0x418487E7                      http://www.nick-andrew.net/
PGP Key fingerprint = B3ED 6894 8E49 1770 C24A  67E3 6266 6EB9 4184 87E7

Re: [RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Ingo Molnar]

* Nick Andrew <nick@nick-andrew.net> wrote:

> > Btw., that's rather arcane text - do people still have to use pirq= 
> > boot lines to get their boxes to boot?
> 
> I wouldn't know that, but I still have to use 'noapic' to get my AMD 
> box to boot :-(

oh. If "noapic" is still necessary with x86/latest:

  http://people.redhat.com/mingo/x86.git/README

is there any bugreport i could have a look at, with full dmesg and 
config included, and with a description of how it fails to boot? 
cfs-debug-info output would be useful too:

  http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh

	Ingo

Re: [RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Nick Andrew]

On Mon, Apr 14, 2008 at 11:46:03AM +0200, Ingo Molnar wrote:
> * Nick Andrew <nick@nick-andrew.net> wrote:
> > I wouldn't know that, but I still have to use 'noapic' to get my AMD 
> > box to boot :-(
> 
> oh. If "noapic" is still necessary with x86/latest:
> 
>   http://people.redhat.com/mingo/x86.git/README

Thanks; I'll retest on latest then. I didn't realise the problem was
fixed.

Nick.
-- 
PGP Key ID = 0x418487E7                      http://www.nick-andrew.net/
PGP Key fingerprint = B3ED 6894 8E49 1770 C24A  67E3 6266 6EB9 4184 87E7

Re: [RFC] x86: Cleanup prose of Documentation/i386/IO-APIC.txt

[Ingo Molnar]

* Nick Andrew <nick@nick-andrew.net> wrote:

> On Mon, Apr 14, 2008 at 11:46:03AM +0200, Ingo Molnar wrote:
> > * Nick Andrew <nick@nick-andrew.net> wrote:
> > > I wouldn't know that, but I still have to use 'noapic' to get my AMD 
> > > box to boot :-(
> > 
> > oh. If "noapic" is still necessary with x86/latest:
> > 
> >   http://people.redhat.com/mingo/x86.git/README
> 
> Thanks; I'll retest on latest then. I didn't realise the problem was 
> fixed.

just to make sure: nothing _specific_ was done in this area, this is 
just to make sure we'll both deal with the same codebase. But in 
general, if a box needs "noapic", that signals a bug we should try to 
solve in the kernel automatically (even if it's BIOS inflicted damage).

	Ingo