boot option for CONFIG_EDD_SKIP_MBR?

boot option for CONFIG_EDD_SKIP_MBR?

[Carl-Daniel Hailfinger]

Hi Matt,

[please CC: me on replies]
having had problems (inifinte hang on boot) with some Fujitsu
Siemens Scenic computers when EDD was enabled, I asked myself
if it would be possible to add a boot option edd=nombr and
possibly also another boot option edd=off to the EDD code in
the kernel. These would correspond to CONFIG_EDD_SKIP_MBR
and CONFIG_EDD, respectively.
That way, distributors could use the benefits of enabled
EDD on working machines and provide customers with the
ability to switch off EDD on broken machines, all with the
same kernel.
Yes, option parsing before entering protected mode is ugly,
but the vga setup code does it, too.

What do you think?

Regards,
Carl-Daniel
-- 
http://www.hailfinger.org/

Re: boot option for CONFIG_EDD_SKIP_MBR?

[Matt Domsch]

On Thu, Nov 04, 2004 at 02:35:58PM +0100, Carl-Daniel Hailfinger wrote:
> [please CC: me on replies]
> having had problems (inifinte hang on boot) with some Fujitsu
> Siemens Scenic computers when EDD was enabled, I asked myself
> if it would be possible to add a boot option edd=nombr and
> possibly also another boot option edd=off to the EDD code in
> the kernel. These would correspond to CONFIG_EDD_SKIP_MBR
> and CONFIG_EDD, respectively.
>
> Yes, option parsing before entering protected mode is ugly,
> but the vga setup code does it, too.
> 
> What do you think?

I'd love it.  I hadn't done it as I thought it would be ugly, and so
far I could blame buggy BIOSes for the delay.  If you want to work up
a patch, I'll gladly review and apply something that does such.

Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer, Lead Engineer
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

Re: boot option for CONFIG_EDD_SKIP_MBR?

[Dave Jones]

On Thu, Nov 04, 2004 at 07:45:34AM -0600, Matt Domsch wrote:
 > On Thu, Nov 04, 2004 at 02:35:58PM +0100, Carl-Daniel Hailfinger wrote:
 > > [please CC: me on replies]
 > > having had problems (inifinte hang on boot) with some Fujitsu
 > > Siemens Scenic computers when EDD was enabled, I asked myself
 > > if it would be possible to add a boot option edd=nombr and
 > > possibly also another boot option edd=off to the EDD code in
 > > the kernel. These would correspond to CONFIG_EDD_SKIP_MBR
 > > and CONFIG_EDD, respectively.
 > >
 > > Yes, option parsing before entering protected mode is ugly,
 > > but the vga setup code does it, too.
 > > 
 > > What do you think?
 > 
 > I'd love it.  I hadn't done it as I thought it would be ugly, and so
 > far I could blame buggy BIOSes for the delay.  If you want to work up
 > a patch, I'll gladly review and apply something that does such.

But would this actually be useful for the cases where EDD has been
broken so far ? AFAIR, the bootparam parsing happens /after/
we do the 16-bit EDD asm foo.

		Dave

Re: boot option for CONFIG_EDD_SKIP_MBR?

[Carl-Daniel Hailfinger]

Dave Jones schrieb:
> On Thu, Nov 04, 2004 at 07:45:34AM -0600, Matt Domsch wrote:
>  > On Thu, Nov 04, 2004 at 02:35:58PM +0100, Carl-Daniel Hailfinger wrote:
>  > > [please CC: me on replies]
>  > > having had problems (inifinte hang on boot) with some Fujitsu
>  > > Siemens Scenic computers when EDD was enabled, I asked myself
>  > > if it would be possible to add a boot option edd=nombr and
>  > > possibly also another boot option edd=off to the EDD code in
>  > > the kernel. These would correspond to CONFIG_EDD_SKIP_MBR
>  > > and CONFIG_EDD, respectively.
>  > >
>  > > Yes, option parsing before entering protected mode is ugly,
>  > > but the vga setup code does it, too.
>  > > 
>  > > What do you think?
>  > 
>  > I'd love it.  I hadn't done it as I thought it would be ugly, and so
>  > far I could blame buggy BIOSes for the delay.  If you want to work up
>  > a patch, I'll gladly review and apply something that does such.
> 
> But would this actually be useful for the cases where EDD has been
> broken so far ? AFAIR, the bootparam parsing happens /after/
> we do the 16-bit EDD asm foo.

AFAIR the VGA setup code does its bootparam parsing by hand because it
suffers from the same problem.

Regards,
Carl-Daniel
-- 
http://www.hailfinger.org/