From: Robert Johnson <rjohnson@sierraphotonics.com>
To: "linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>
Subject: PowerPC PPC32 CONFIG_HIGHMEM dependency question
Date: Mon, 17 Mar 2014 17:41:25 +0000 [thread overview]
Message-ID: <d23eabd04d35481db8b483f9630341fd@SPIEXCHMAIL01.sierraphotonics.com> (raw)
I am using an embedded single board computer (SBC) that has a Freescale P2020 processor. The vendor board support package (BSP) for this product currently uses a 3.0.4 Linux kernel. In looking through the RT patch for various Linux kernel versions even up through 3.12.13-rt21, I see that CONFIG_HIGHMEM is not allowed if CONFIG_PREEMPT_RT_FULL is selected (see arch/powerpc/Kconfig).
The result for my SBC is that if I enable CONFIG_PREEMPT_RT_FULL in the kernel, I am then only able to access 1GB of RAM instead of the 4GB that is resident.
Is there any way to get CONFIG_PREEMPT_RT_FULL to work with CONFIG_HIGHMEM?
If I want to use CONFIG_HIGHMEM, should I consider the use of CONFIG_PREEMPT_RTB which does not appear to have a dependency?
next reply other threads:[~2014-03-17 17:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-17 17:41 Robert Johnson [this message]
2014-03-18 10:54 ` PowerPC PPC32 CONFIG_HIGHMEM dependency question Sebastian Andrzej Siewior
2014-03-21 15:12 ` Robert Johnson
2014-03-21 20:02 ` Sebastian Andrzej Siewior
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=d23eabd04d35481db8b483f9630341fd@SPIEXCHMAIL01.sierraphotonics.com \
--to=rjohnson@sierraphotonics.com \
--cc=linux-rt-users@vger.kernel.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).