lkml.org 
[lkml]   [2008]   [Jun]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ACPI: don't walk tables if ACPI was disabled
On Fri, Jun 20, 2008 at 10:40 PM, Vegard Nossum <vegard.nossum@gmail.com> wrote:
> On Fri, Jun 20, 2008 at 9:00 PM, Len Brown <lenb@kernel.org> wrote:
>>> @@ -333,6 +333,9 @@ static int __init acpi_rtc_init(void)
>>> {
>>> struct device *dev = get_rtc_dev();
>>>
>>> + if (acpi_disabled)
>>> + return 0;
>>> +
>>
>> hmm, i would expect dev to be 0 for acpi=off,
>> since pnp_match would fail, no?
>
> Obviously not. Because Ingo is booting with acpi=off and he still gets
> a warning about some mutex operation that originates from this very
> initcall:
>
> [ 3.976213] calling acpi_rtc_init+0x0/0xd3
> [ 3.980213] ACPI Exception (utmutex-0263): AE_BAD_PARAMETER, Thread
> F7C50000 could not acquire Mutex [3] [20080321]
>
>

Aha. The device in question (PNP0b00) is discovered while doing
pnpbios_init(), NOT pnpacpi_init:

[ 1.712032] initcall pnpacpi_init+0x0/0x80 returned 0 after 3 msecs
[ 1.716032] calling pnpbios_init+0x0/0x322
[ 1.720032] PnPBIOS: Scanning system for PnP BIOS support...
[ 1.724032] PnPBIOS: Found PnP BIOS installation structure at 0xc00fc550
[ 1.728032] PnPBIOS: PnP BIOS version 1.0, entry 0xf0000:0xc580, dseg 0xf0000
...
[ 1.876032] pnp 00:03: parse allocated resources
[ 1.880032] pnp 00:03: add irq 8 flags 0x0
[ 1.884032] pnp 00:03: add io 0x70-0x71 flags 0x0
[ 1.888032] pnp 00:03: parse resource options
[ 1.892032] pnp 00:03: new independent option
[ 1.896032] device: '00:03': device_add
[ 1.900032] bus: 'pnp': add device 00:03
[ 1.904032] PM: Adding info for pnp:00:03
[ 1.908032] pnp 00:03: Plug and Play BIOS device, IDs PNP0b00 (active)

So I guess this function, pnpbios_init() needs the check as well. In
fact, it has this:

#ifdef CONFIG_PNPACPI
if (!acpi_disabled && !pnpacpi_disabled) {
pnpbios_disabled = 1;
printk(KERN_INFO "PnPBIOS: Disabled by ACPI PNP\n");
return -ENODEV;
}
#endif /* CONFIG_ACPI */

...I guess that should be changed to say if (acpi_disabled ||
pnpacpi_disabled)? Or... I don't understand the purpose of the
original test. But it seems to be there since the beginning of time
(or, well, v2.6.12-rc2).


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036


\
 
 \ /
  Last update: 2008-06-20 23:29    [W:0.094 / U:0.280 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site