i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new features not supported

[Andriy Gapon]

The following reply was made to PR i386/135447; it has been noted by GNATS.

From: Andriy Gapon <avg at freebsd.org>
To: Dmitry Kubov <dk at garant.ru>, Alexander Motin <mav at freebsd.org>
Cc: jh at freebsd.org, bug-followup at freebsd.org
Subject: Re: i386/135447: [i386] [request] Intel Core i7 and Nehalem-EP new
 features not supported
Date: Mon, 20 Sep 2010 18:11:20 +0300

 on 20/09/2010 17:54 Dmitry Kubov said the following:
 > dev.cpu.7.cx_supported: C1/3 C2/205 C3/245
 Note these------------------------^^^----^^^
 > dev.cpu.7.cx_lowest: C3
 > dev.cpu.7.cx_usage: 100.00% 0.00% 0.00% last 500us
 And this --------------------------------------^^^^^
 > C2/C3 not used at all
 
 And now there is this code in acpi_cpu.c:
 
     /* Find the lowest state that has small enough latency. */
     cx_next_idx = 0;
     for (i = sc->cpu_cx_lowest; i >= 0; i--) {
         if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
             cx_next_idx = i;
             break;
         }
     }
 
 205 * 3 and 245 * 3 are both greater than 500, so this is the reason why they are
 never entered.
 
 Perhaps Alexander can give some advice here.
 
 -- 
 Andriy Gapon