From: Thomas Renninger <email@example.com>
To: Bjorn Helgaas <firstname.lastname@example.org>
Cc: Rene Herman <email@example.com>,
"Li, Shaohua" <firstname.lastname@example.org>
Subject: Re: [PATCH] Declare PNP option parsing functions as __init
Date: Sun, 02 Dec 2007 14:32:07 +0100 [thread overview]
Message-ID: <email@example.com> (raw)
On Fri, 2007-11-30 at 16:52 -0700, Bjorn Helgaas wrote:
> On Friday 30 November 2007 04:37:26 pm Rene Herman wrote:
> > On 30-11-07 18:04, Thomas Renninger wrote:
> > > If I have not overseen something, it should be rather obvious that those
> > > can all be declared __init...
> > > ---------------
> > >
> > > Declare PNP option parsing functions as __init
> > >
> > > There are three kind of parse functions provided by PNP acpi/bios:
> > > - get current resources
> > > - set resources
> > > - get possible resources
> > > The first two may be needed later at runtime.
> > > The possible resource settings should never change dynamically.
> > > And even if this would make any sense (I doubt it), the current implementation
> > > only parses possible resource settings at early init time:
> > > -> declare all the option parsing __init
> > >
> > > Signed-off-by: Thomas Renninger <firstname.lastname@example.org>
> > Yes. Obviousness aside,
> > (0) pnpacpi_add_device is only caller of
> > ...
> I agree this is probably safe in the current implementation.
> However, I think the current implementation is just broken because
> we can't really handle hotplug of ACPI devices. Specifically, I think
> the first TBD in acpi_bus_check_device() should be fleshed out so it
> does something like pnpacpi_add_device().
Yes, making the ACPI layer more hotplug capable is something that should
be worked on again.
> So my dissenting opinion is that this patch would just get reverted
> soon anyway when somebody finishes implementing ACPI hotplug, and
> therefore it's not worth doing.
Yes you are right. I thought _PSR could always be called at init time,
whether present or not (which would certainly work for most/all devices
as _PSR info should be kind of static), but ACPI spec forbids it:
6.3.7 _STA (Status)
If bit 0 is cleared, then bit 1 must also be cleared (in other words, a
device that is not present cannot be enabled).
A device can only decode its hardware resources if both bits 0 and 1 are
set. If the device is not present (bit 0 cleared) or not enabled (bit 1
cleared), then the device must not decode its resources.
I only saw:
6.2.10 _PRS (Possible Resource Settings):
If the device is disabled when _PRS is called, it must remain disabled.
But disabled and not present are different things...
It's stupid as the possible resources of a device will always remain the
same, whether it is present or not, but if it is written down in the
spec, there is not much to argue about it...
next prev parent reply other threads:[~2007-12-02 13:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-30 17:04 [PATCH] Declare PNP option parsing functions as __init Thomas Renninger
2007-11-30 23:37 ` Rene Herman
2007-11-30 23:52 ` Bjorn Helgaas
2007-12-01 0:33 ` Rene Herman
2007-12-02 13:34 ` Thomas Renninger
2007-12-02 13:50 ` Rene Herman
2007-12-02 13:32 ` Thomas Renninger [this message]
2007-12-03 11:53 ` Thomas Renninger
2007-12-03 15:52 ` Bjorn Helgaas
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:
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
* 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).