Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

From: Pavel Machek
Date: Mon Dec 17 2007 - 08:31:37 EST


On Mon 2007-12-17 14:22:26, Rene Herman wrote:
> On 17-12-07 14:09, Ingo Molnar wrote:
>
>>>> -#ifndef CONFIG_UDELAY_IO_DELAY
>>>> -static int __init dmi_alternate_io_delay_port(const struct
>>>> dmi_system_id *id)
>>>> +static int __init dmi_io_delay_0xed_port(const struct dmi_system_id
>>>> *id)
>>>> {
>>>> - printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident);
>>>> - io_delay = alternate_io_delay;
>>>> + printk(KERN_NOTICE "%s: using 0xed I/O delay port\n", id->ident);
>>>> + io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
>>>> +
>>>> return 0;
>>>> }
>>> This isn't correct. DMI shouldn't override the CONFIG choice or someone
>>> with matching DMI will have a defective CONFIG option. That's why I put
>>> all of it inside #ifndef.
>> no, the DMI quirk is just that: a quirk that makes boxes work. The DMI
>> quirk takes precedence over just about any .config default, except an
>> explicit boot-commandline override.
>
> No, most definitely not. Having the user select udelay or none through the
> kernel config and then the kernel deciding "ah, you know what, I'll know
> better and use port access anyway" is _utterly_ broken behaviour. Software
> needs to listen to its master.

That's what command line is for. Ingo is right here.
Pavel
--
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