linux-kernel - Re: [patch 22/53] PNP: factor pnp_init_resource_table() and pnp_clean_resource

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Date:	Wed, 23 Apr 2008 17:08:53 -0600
From:	Bjorn Helgaas <bjorn.helgaas@...com>
To:	Rene Herman <rene.herman@...access.nl>
Cc:	Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, Adam Belay <ambx1@....rr.com>,
	Li Shaohua <shaohua.li@...el.com>,
	Matthieu Castet <castet.matthieu@...e.fr>,
	Thomas Renninger <trenn@...e.de>,
	Jaroslav Kysela <perex@...ex.cz>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [patch 22/53] PNP: factor pnp_init_resource_table() and pnp_clean_resource_table()

On Tuesday 22 April 2008 03:01:58 pm Rene Herman wrote:
> It seems you designed the list to be basically in any order, judging by 
> things such as pnp_new_resource which'll happily reuse resources of the 
> correct type at any position in the list. Yet, pnp_assign_foo() and friends 
> retrieve resources (through pnp_get_resource) by position in the list and 
> not by the index. I'm not overly sure of failure scenarios but isn't this 
> mixing up position and index in a bad way?

Yes, I think you're right.

My idea is that the list should end up in the same order as the
resource list from the BIOS, e.g., the _CRS and _PRS lists for
ACPI.  In the case of ISAPNP, it'll be in the order that we read
things from the hardware registers.

I think I should probably make pnp_new_resource() always allocate
a new resource and get rid of the idea of reusing something already
in the list.

> >> (do note that pnp_assign_foo are the only callers of pnp_check_foo and they 
> >> could be either merged together or at least not communicate via "idx" but 
> >> simply by passing the res/pnp_res).
> > 
> > Yes, I'd like to do that.  But I think I'd better wait or I'll never
> > get anything finished :-)
> 
> Well, the idea here was that getting rid of one "idx" here so that things 
> communicate directly removes at least one possible ordering artifact...

Yup.  I ended up doing this after all.

I updated the patches and my ACPI box with the inactive devices now
boots (it failed with the v3 patches).  I'll work on the
pnp_new_resource() thing tomorrow, but I'll send you the current
patches now in case you have a chance to try them on your ISA box.

Bjorn
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