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Bug 4546

Summary: A fix for APM on Acer Extensa 501T and possibly others.
Product: [Retired] Red Hat Linux Reporter: Michael McConachie <michael>
Component: kernelAssignee: Michael K. Johnson <johnsonm>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 6.0CC: claudiol
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2000-02-04 03:10:46 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Michael McConachie 1999-08-16 16:09:24 UTC
This ended up comming in over a support ticket.  The
informations eems to be quite valid.  Submitted as a bug in
case it's any use to others...

Bios of "ACER EXTENSA 501T"
return     apm_bios_info.cseg=0xfbbd and
apm_bios_info.offset=0x500000
(this is bad adress)
working is apm_bios_info.cseg=0xfbbd and
apm_bios_info.offset=0

--- apm.c.orig  Fri Jan 15 07:57:25 1999
+++ apm.c       Mon Jun 28 14:36:29 1999
@@ -1349,7 +1349,7 @@
                 __va((unsigned long)0x40 << 4));
        _set_limit((char *)&gdt[APM_40 >> 3], 4095 - (0x40
<< 4));

-       apm_bios_entry.offset = apm_bios_info.offset;
+       apm_bios_entry.offset = apm_bios_info.offset &
0xffff;
        apm_bios_entry.segment = APM_CS;
        set_base(gdt[APM_CS >> 3],
                 __va((unsigned long)apm_bios_info.cseg <<
4));

--

References: http://www.al.unipmn.it/~sitta/linux503.html
            http://www.al.unipmn.it/~sitta/linux/apm.html

   --michael

Comment 1 Michael K. Johnson 1999-09-25 04:44:59 UTC
Doug, could you please evaluate this?

Comment 2 Bernhard Rosenkraenzer 1999-11-12 18:21:59 UTC
Kernel problem, not apmd.
Doesn't apply to current kernel - guess we can close this?

Comment 3 Bernhard Rosenkraenzer 2000-01-31 20:10:59 UTC
This is a kernel problem - it's fixed in 2.3.x (CONFIG_APM_BAD_ENTRY_OFFSET),
but it's still present in kernel 2.2.14.
The patch mentioned above doesn't apply to current 2.2 kernels;
the line in question is line 1353 in arch/i386/kernel/apm.c 2.2.14-1.2.0.
I don't see a problem with this patch - IMO it can get in.

Comment 4 Alan Cox 2000-08-22 14:31:30 UTC
Its already handled differently in current 2.2