[PATCH 0/9] (mostly) x86 kernel configuration adjustments

[Elliott Mitchell]

On Thu, Apr 27, 2023 at 01:11:13AM +0200, Stefan Lippers-Hollmann wrote:
> On 2023-04-26, Elliott Mitchell wrote:
> [...]
> > 
> > Looks like little of ISA remained on "64", yet some DMA support remained
> > due to the generic configuration.  Remove the ISA and ISA DMA support
> > from the top-level configuration.  Geode and Legacy though almost
> > certainly still need ISA support.
> 
> You might find that while ISA went away as an addon slot quite quickly,
> it still survived rather long for low performance onboard devices (e.g. 
> sensors).

I know, I was unsure of when it 100% disappeared.  Do you expect anything
besides "legacy" to be used for this type of system though?

My larger concern is the x86 default should be "no" since this is less
than 50% of cases.  As such target/linux/x86/config-* should have
CONFIG_ISA=n and only the special builds which need it should enable it.


> > In case someone doesn't know, "AGP" is short for "Accelerated Graphics
> > Port".  This was an interim standard when graphics cards in the late
> > 1990s were overwhelming PCI, but PCI-Express wasn't yet available.  Since
> > OpenWRT is a router distribution, this doesn't seem like a good fit.  If
> > you've got such an Intel board, this will reduce graphics performance,
> > but will release ~.5MB extra memory for better uses.
> 
> While *I personally* wouldn't consider systems of this vintage for 24/7
> operations (power consumption alone), AGP has been in use for quite a 
> while longer than that (mid 2000s). I do still have (fully functional) 
> Pentium 4 and AMD64 systems with AGP graphics.

Mine are long gone.  I believe AGP though is a PCI superset.  Disabling
AGP support is supposed to reduce performance, but keep the bus
functional.  Mainly it merely behaves as a very fast PCI bus instead of
having extra features.

There has been discussion of removing AGP support from the Linux kernel.

> I have responded to DRM and x86_x32 individually, but while I understand 
> these proposals from a virtualization-only point of view, they are not
> very useful on real x86/ x86_64 hardware - up to the point of being 
> actively harmful in breaking support for existing hardware.

Please point to a patch and cite an example of existing hardware it
breaks*.

* reduced performance is not breaking support, pushing hardware onto
legacy isn't breaking support either


> (It's pointless to enable x32, unless you can demonstrate that OpenWrt's
> buildsystem can successfully build for it, with a 32 bit userland and
> 64 bit kernels).

Enabling the kernel support is the first step in the process of getting
x32 operational.


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