Steven et al,
Summary: dmi_scan.c forces interrupt enable on during PCI BIOS call for
all IBM machines, which breaks T23, which needs it off it seems.
(Steven: hope you don't mind lkml copy)
>>> My only worry is I have some people saying (admittedly on laptops
>>> pre the T23) that disabling this opption whilst udma is still enabled
>>> is a sure way to kill your entire filing system. Well, guess I've
>>> got most of it backed up ...
>>
>> You could try this in single user mode with all your file systems mounted
>> read only (or not mounted if possible).
>
> I will try it this evening - I think with UDMA off (somehow), single
> user mode, no other apps, immediate reboot afterwards,
> it should be worth the risk :-)
>
> I have 2 x T23 here which are not (yet) doing vital stuff, so if you
> want any information on them, I'm happy to do testing.
Well, lo and behold, if I /do/ disable interrupts (i.e. change
APM_DO_CLI to just cli() ), it seems to suspend and restore
correctly. So it looks like the BIOS in the T23 has the opposite
bug from other boxes - i.e. it doesn't work if you have interrupts
/enabled/ (grrrr...).
So now 'all' I have to worry is all the dire warnings about
enabling this.
>>> I shall try it - is this any different (I think no) from turning OFF
>>> the config option which says enable IRQs in interrupts?
>>
>> It is different, because we automatically detect all IBM thinkpads and
>> turn that option on at runtime. We currently do not distinguish between
>> different Thinkpad models because up until (at least) the T22, they all
>> had the problem and I do not have access to a T23.
>
> OK - obviously hadn't read the code sufficiently closely.
Found it :-)
Looks like the test for IBM laptops in dmiscan.c is too specific,
and needs to be made less so. I changed dmi_printk
to just do a printk() and have included what I think is all
the relevant information below, so you can exclude matching the T23.
I have attached a patch which fixes this (against 2.4.12-ac5),
and the dmi dump.
-- Alex BlighDMI dump on standard build:
All processors have done init_idle DMI 0.0 present. 48 structures occupying 1720 bytes. DMI table at 0x27F7C000. BIOS Vendor: IBM BIOS Version: 1AET38WW (1.01b) BIOS Release: 07/27/2001 System Vendor: IBM. Product Name: 26479LU. Version Not Available. Serial Number 787PR4K. Board Vendor: IBM. Board Name: 26479LU. Board Version: Not Available. Asset Tag: No Asset Information. IBM machine detected. Enabling interrupts during APM calls.
--- kernel-source-2.4.12ac5clean/arch/i386/kernel/dmi_scan.c Tue Oct 23 10:00:14 2001 +++ kernel-source-2.4.12ac5dev/arch/i386/kernel/dmi_scan.c Wed Oct 31 22:09:14 2001 @@ -277,6 +277,23 @@ return 0; }
+/* + * ... but some other (more specific) variants of the above laptops + * do not like interrupts being enabled during APM calls + * For instance though IBM laptops apparently crash if interrupts + * are not enabled during APM calls, the IBM T23 appears to crash + * if interrupts /are/ enabled during APM calls - sigh - alex@alex.org.uk + */ +static __init int set_no_apm_ints(struct dmi_blacklist *d) +{ + if (apm_info.allow_ints) + { + apm_info.allow_ints = 0; + printk(KERN_INFO "%s machine detected. Re-disabling interrupts during APM calls.\n", d->ident); + } + return 0; +} + /* * Some APM bioses corrupt memory or just plain do not work */ @@ -458,6 +475,11 @@ MATCH(DMI_SYS_VENDOR, "IBM"), NO_MATCH, NO_MATCH, NO_MATCH } }, + { set_no_apm_ints, "IBM T23", { /* Disable interrupts during suspend on IBM T23 laptops */ + MATCH(DMI_SYS_VENDOR, "IBM"), + MATCH(DMI_PRODUCT_NAME, "26479"), + NO_MATCH, NO_MATCH + } }, { set_apm_ints, "Dell Inspiron", { /* Allow interrupts during suspend on Dell Inspiron laptops*/ MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), MATCH(DMI_PRODUCT_NAME, "Inspiron 4000"),
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This archive was generated by hypermail 2b29 : Wed Nov 07 2001 - 21:00:21 EST