lkml.org 
[lkml]   [2000]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Why is double_fault serviced by a trap gate?
On Thu, 7 Dec 2000, Andi Kleen wrote:

> Interesting. One of my ports references for PCs lists
>
> 0044 r/w PIT counter 3 (PS/2, EISA)
> used as fail-safe timer. generates an NMI on time out.
> for user generated NMI see at 0462.

Oh no, we don't use that. Even though we could, it's rare -- it exists
for EISA systems only and then mostly older ones (i.e. non-PCI ones).

In fact the only chipset that provides these additional NMI sources I
have docs for is the i82350 one.

> I don't know if modern PCs still provide this counter, but if yes it could
> be used for a slow NMI watchdog that only runs every 30s or so.

An ability to choose a NMI frequency, especially such a low one, would be
desirable but it is really inexistent for most IA32 systems.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +

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

\
 
 \ /
  Last update: 2005-03-22 12:51    [W:0.026 / U:13.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site