From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Gerhard Pircher <gerhard_pircher@gmx.net>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: How to dynamically disable/enable CPU features?
Date: Sat, 23 Feb 2008 09:26:19 +1100 [thread overview]
Message-ID: <1203719179.6976.25.camel@pasglop> (raw)
In-Reply-To: <20080221200758.62940@gmx.net>
On Thu, 2008-02-21 at 21:07 +0100, Gerhard Pircher wrote:
> Hi,
>
> I'm wondering how to disable or enable CPU features based on the board the
> kernel is running on. In my case I want to disable the
> CPU_FTR_NEED_COHERENT flag for 74xx CPUs, because it locks up the machine.
> I tried to clear the flag in the platform's *_probe() function with the
> following code:
>
> cur_cpu_spec->cpu_features &= ~CPU_FTR_NEED_COHERENT;
That works on 64 bits but unfortunately not on 32 bits. This is a
longstanding issue that we need to fix. ie. we need to move the
fixups later in the boot process (if possible put them in the
same place for 32 and 64 bits), though that needs to be done very
carefully, making sure nothing that requires those fixups ends up
happening before they happen as a result of the move.
Ben.
prev parent reply other threads:[~2008-02-22 22:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-21 20:07 How to dynamically disable/enable CPU features? Gerhard Pircher
2008-02-22 17:24 ` Milton Miller
2008-02-22 19:05 ` Gerhard Pircher
2008-02-22 22:32 ` Benjamin Herrenschmidt
2008-02-24 14:47 ` Gerhard Pircher
2008-02-22 22:26 ` Benjamin Herrenschmidt [this message]
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=1203719179.6976.25.camel@pasglop \
--to=benh@kernel.crashing.org \
--cc=gerhard_pircher@gmx.net \
--cc=linuxppc-dev@ozlabs.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).