amd64/171355: FreeBSD 9.1rc1 (and 10-HEAD) not booting on HP Pavilion g6 2147sl

[Alexander Motin]

The following reply was made to PR amd64/171355; it has been noted by GNATS.

From: Alexander Motin <mav at FreeBSD.org>
To: Stefano Marinelli <stefano at dragas.it>
Cc: attilio at freebsd.org, bug-followup at FreeBSD.org
Subject: Re: amd64/171355: FreeBSD 9.1rc1 (and 10-HEAD) not booting on HP
 Pavilion g6 2147sl
Date: Sun, 09 Sep 2012 23:22:39 +0300

 On 09.09.2012 23:17, Stefano Marinelli wrote:
 >> There could be other factors except CPU. For example, GPU, screen backlight, disks, etc. Without having proper video driver for AMD GPUs it is difficult to predict its power consumption. Also you may look on this page: http://wiki.freebsd.org/TuningPowerConsumption . It was written some time ago and mostly for Intel, but hopefully better then nothing. Unluckily I have no experience with AMD laptops.
 >
 > Actually I think it's a matter of GPU. On Linux, I can use the proprietary drivers. On (PC|Free)BSD, I am using the VESA XOrg driver.
 > The link you gave me allowed me, some time ago, to lower my netbook power consumption, going even lower than Linux.
 >
 > The machine is compiling the patched kernel now. I will try to reboot it as soon as finished.
 
 That patch should just block HPET to allow booting without tunables. 
 Thanks for testing the patch, but that is not so interesting from 
 practical side. What I would try to do after that is switch HPET into 
 legacy_route mode that was known to work on previous AMDs:
 hint.hpet.0.legacy_route=1
 hint.attimer.0.clock=0
 hint.atrtc.0.clock=0
 
 AFAIK, that is what Linux uses by default when it uses HPET.
 
 -- 
 Alexander Motin