lkml.org 
[lkml]   [1999]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: resending patch: Documentation/pci.txt
Date
Alan Cox [mailto:alan@lxorguk.ukuu.org.uk] wrote:
> > Damn it! The name appears to have changed between 2.2 and 2.3.
>
> It did. That maybe good to note

Yeah, and also goes a long way towards explaining why my documentation
changes never went anywhere.

They are wrong for 2.3, but mostly right for 2.2.

Shall I resubmit them as a patch to 2.2 documentation, taking out the stuff
about check_/request_/release_*_region? Or am I still misunderstanding
something in the 2.2 kernel?

> > In pci.h the struct in 2.2.13 (and I would assume later) had
> >
> > unsigned long base_address[6]
> >
> > which cooresponded to the various PCI Base Address Registers.
> >
> > Why did this change, and what was wrong with the old
> base_address[] array?
> > Since every PCI driver is supposed to get the address from
> this field, I
> > think this is a legitimate question.
>
> 2.2.x you get the value from the PCI registers. Its a copy of
> the BAR with flags

Actually, this isn't what I understood Martin to have told me. I had written
him on this exact point to get clarification.

It is a 'converted BAR', not the value in the PCI BAR. It is the physical
address on that system bus, although someone mentioned this should probably
be treated more as a cookie in order to be architechure neutral.

In any case, on 2.2.x I was told that it was the value to pass into
ioremap().

> With 2.3.x you get told the start/end/size of each resource
> and if it is
> I/O or memory. Resource objects are portable for all busses.
> Also they do the
> things like 64bit using dual BAR's properly for you, and they
> can do magic
> mappings as needed.

Great. Sounds like someone should document this somewhere.

Going to make for a reasonable amount of ifdefs() in drivers that are used
on both 2.2 and the development kernel. Yuck.

-Bret

-------------------------------------------------------------
SBS Technologies, Connectivity Products
... solutions for real-time connectivity

Bret Indrelee, Engineer
SBS Technologies, Inc., Connectivity Products
1284 Corporate Center Drive, St. Paul MN 55121
Direct: (651) 905-4731
Main: (651) 905-4700 Fax: (651) 905-4701
E-mail: bindrelee@sbs-cp.com http://www.sbs.com
-------------------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:55    [W:0.034 / U:0.804 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site