lkml.org 
[lkml]   [2009]   [Apr]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/3] pci: don't assume pref memio are 64bit -v2

* Ivan Kokshaysky <ink@jurassic.park.msu.ru> wrote:

> On Sat, Apr 18, 2009 at 01:44:51AM -0700, Yinghai Lu wrote:
> > and BIOS set
> > [ 0.240007] pci 0000:00:01.0: bridge 64bit mmio pref: [0xbdf00000-0xddefffff]
>
> An obvious BIOS bug, the bridge base overlaps the physical low RAM
> (0x00000000-0xc0000000). Technically speaking, this nonsense
> *happens* to work on Intel hardware, so it seems to be quite
> common bug nowadays - BIOS writers get lost in ACPI and other
> "useful" stuff contradicting the PCI specs.

it doesnt matter whether we call it a BIOS bug or not.

> ...
>
> > + /* don't allocate too high if the pref mem doesn't support 64bit*/
> > + if ((res->flags & (IORESOURCE_PREFETCH | PCI_PREF_RANGE_TYPE_64)) ==
> > + IORESOURCE_PREFETCH)
> > + max = 0xffffffff;
>
> This effectively destroys non-x86 64-bit arches. You've been told about
> that before, so I'm really surprised to see this "patch" once again.
>
> Categorically NACKed.

You can ridicule the patch and can NAK it (and rightfully so, it's
wrong), but you seem to miss the simple fact that this solves a very
real problem.

So consider this patch a documentation and analysis of a real
problem which made Linux work on hardware where it did not work
before. That's more valuable than 95% of our commits btw.

> P.S. I recall that I had a patch that addressed the issue, and
> Ingo made some reasonable comments about it. Will post it
> tomorrow.

That should have been pursued far more agressively.

Thanks,

Ingo


\
 
 \ /
  Last update: 2009-04-18 22:29    [W:0.050 / U:1.396 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site