Re: [RFC PATCH 02/15] x86/apic: Fix smp init delay for extended Intel families

[Dave Hansen]

On 12/20/24 13:36, Sohil Mehta wrote:
> The MP specification version 1.4 references the i486 and early Pentium
> processors in family 5. 

Can you please elaborate on how this reference is relevant to the patch
at hand?

> However, all processors starting with family 6 likely do not need the
> 10 msec INIT delay. The omission of the Pentium 4s (family 15) seems
> like an oversight in the original check.
> 
> With some risk, choose a simpler check and extend the quirk to all
> recent and upcoming Intel processors.

I'm struggling to follow this a bit.

I think these are the facts that matter:

 * init_udelay=0 means "no quirk"
 * Modern CPUs don't have the quirk
 * The current check says "only family 6 is modern"
 * Family 15 is _probably_ modern and just forgotten about

And this is what you're doing in the end:

Consider everything PPro and later to be modern, including all of
families 6, 15 and the new 18/19 CPUs.

Right?