DSDT loading patch

DSDT loading patch

[David Goodenough]

I recently bought my eldest son a Samsung P28 laptop, which works just fine
with Linux except of course that it suffers from a badly built DSDT.  I have
found instructions as to how to fix it and found that this required me to 
add in a patch to the kernel to allow a DSDT image to be appended to the
initrd image.  This patch seems to have been around for a long time and 
judging by the number of machines listed as needing to have their DSDT
updated there is a need to have this patch in the standard kernel.  Is there
a reason why this patch has not been included?

The most useful page I found that describes this particular patch was 
http://gaugusch.at/kernel.shtml, which says that SuSE now include the
patch anyway, and that Mandrake are considering it.

David


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Re: DSDT loading patch

[Andrew Barr]

On Monday 06 December 2004 4:07 am, David Goodenough wrote:
> I recently bought my eldest son a Samsung P28 laptop, which works just fine
> with Linux except of course that it suffers from a badly built DSDT.  I
> have found instructions as to how to fix it and found that this required me
> to add in a patch to the kernel to allow a DSDT image to be appended to the
> initrd image.  This patch seems to have been around for a long time and
> judging by the number of machines listed as needing to have their DSDT
> updated there is a need to have this patch in the standard kernel.  Is
> there a reason why this patch has not been included?
>
> The most useful page I found that describes this particular patch was
> http://gaugusch.at/kernel.shtml, which says that SuSE now include the
> patch anyway, and that Mandrake are considering it.
>
> David

There is a feature to compile-in the DSDT included in ACPI patch 20041105. I 
forget if it's in kernel 2.6.9 or not. I think the DSDT-in-initrd technique 
is not recommended anymore.

Andrew


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Re: DSDT loading patch

[David Goodenough]

On Monday 06 December 2004 12:40, Andrew Barr wrote:
> On Monday 06 December 2004 4:07 am, David Goodenough wrote:
> > I recently bought my eldest son a Samsung P28 laptop, which works just
> > fine with Linux except of course that it suffers from a badly built DSDT.
> >  I have found instructions as to how to fix it and found that this
> > required me to add in a patch to the kernel to allow a DSDT image to be
> > appended to the initrd image.  This patch seems to have been around for a
> > long time and judging by the number of machines listed as needing to have
> > their DSDT updated there is a need to have this patch in the standard
> > kernel.  Is there a reason why this patch has not been included?
> >
> > The most useful page I found that describes this particular patch was
> > http://gaugusch.at/kernel.shtml, which says that SuSE now include the
> > patch anyway, and that Mandrake are considering it.
> >
> > David
>
> There is a feature to compile-in the DSDT included in ACPI patch 20041105.
> I forget if it's in kernel 2.6.9 or not. I think the DSDT-in-initrd
> technique is not recommended anymore.
>
> Andrew
Thanks for the reply.  I am glad that some feature to get this in is now
getting in to the standard kernel, but it does strike me that this in-initrd 
method means that normally you would not have to rebuild your kernel
just because you have a buggy DSDT every time you put up a new kernel.
Normally these days I can work with the stock Debian kernels, and so I
do not need to rebuild the kernel every time.

Do you know who decided this and why?

Regards

David


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Re: DSDT loading patch

[Andrew Barr]

On Monday 06 December 2004 9:35 am, David Goodenough wrote:
[...]
> Thanks for the reply.  I am glad that some feature to get this in is now
> getting in to the standard kernel, but it does strike me that this
> in-initrd method means that normally you would not have to rebuild your
> kernel just because you have a buggy DSDT every time you put up a new
> kernel. Normally these days I can work with the stock Debian kernels, and
> so I do not need to rebuild the kernel every time.
>
> Do you know who decided this and why?
>
> Regards
>
> David

You'll only need to rebuild your kernel if your DSDT changes and is still 
buggy: for example, if Samsung updates their BIOS and you upgrade, and 
they've changed the DSDT but not fixed the bugs that the ACPI subsystem had 
problems with.

The initrd method is only adventageous if you are in the process of fixing 
your DSDT and you'd like to test different DSDTs and don't want to recompile 
your kernel each time. The in-kernel method is actually better for me; that 
way I don't have to remeber to append the DSDT to the generated initrd.

The initrd method is no longer used for technical reasons I don't remember 
exactly.

Andrew


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