From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: John Steele Scott <toojays@toojays.net>
Cc: linuxppc-dev list <linuxppc-dev@lists.linuxppc.org>,
Christiaan Welvaart <cjw@daneel.dyndns.org>
Subject: Re: nearly-working support for cpufreq on 2004 iBook G4 with 7447A cpu
Date: Tue, 01 Jun 2004 09:47:12 +1000 [thread overview]
Message-ID: <1086047232.1930.74.camel@gaston> (raw)
In-Reply-To: <200405311807.59356.toojays@toojays.net>
Oh, and when switching to high speed, think about tweaking the
voltage too. I don't know if it's high or low when setting the
GPIO bit, you may want to check out OF code, it certainly have
methods for that. Or you can read the voltage value back from
the adt themometer chip I think, as it does voltage control.
(see cpu-vcore-select GPIO)
I suspect that the machine boots at low speed & low voltage. You
should either set it to high speed in pmac_feature (before bogomips
calculation) or assume it has booted low speed in your driver. You
need to ramp up voltage & wait before swiotching to high speed and
ramp down voltage after switching to low speed.
The delay is unknown, I suppose 100ms should be plenty enough though
(probably even too much).
Ben.
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2004-05-31 23:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-30 14:01 nearly-working support for cpufreq on 2004 iBook G4 with 7447A cpu John Steele Scott
2004-05-30 22:43 ` Benjamin Herrenschmidt
2004-05-30 22:43 ` Benjamin Herrenschmidt
2004-05-31 0:32 ` John Steele Scott
2004-05-31 0:29 ` Benjamin Herrenschmidt
2004-05-31 3:49 ` Benjamin Herrenschmidt
2004-05-31 8:37 ` John Steele Scott
2004-05-31 23:41 ` Benjamin Herrenschmidt
2004-05-31 23:47 ` Benjamin Herrenschmidt [this message]
2004-06-01 2:05 ` nearly-working support for cpufreq on 2004 iBook G4 with 7447Acpu John Steele Scott
2004-06-01 2:53 ` Benjamin Herrenschmidt
2004-06-02 11:08 ` nearly-working support for cpufreq on 2004 iBook G4 with 7447A cpu John Steele Scott
2004-06-03 22:26 ` Benjamin Herrenschmidt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1086047232.1930.74.camel@gaston \
--to=benh@kernel.crashing.org \
--cc=cjw@daneel.dyndns.org \
--cc=linuxppc-dev@lists.linuxppc.org \
--cc=toojays@toojays.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.