Re: [bisected][resend] pnp: Huge number of "io resource overlap"messages

From: Rene Herman
Date: Tue Sep 09 2008 - 07:19:48 EST


This is a multi-part message in MIME format.On 09-09-08 12:50, Frans Pop wrote:
The only thing I used to get for pnp 00:08 on my Toshiba Satellite A40
up to 2.6.26 was this single line:
pnp 00:08: can't add resource for IO 0xa8-0xa9

During bisecting I have found that fairly early in the 2.6.27 cycle this
was "fixed" and that message disappeared. The commit that changed this was:
commit aee3ad815dd291a7193ab01da0f1a30c84d00061
Author: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
Date: Fri Jun 27 16:56:57 2008 -0600
PNP: replace pnp_resource_table with dynamically allocated resources

Was it expected that that change could lead to a message disappearing?
I don't really read that from the commit description.


So far for the intro, now the issue (regression?) that prompted this mail.

Now with 2.6.27-rc4/5 I'm suddenly getting a total of 78 (!) warnings
about "io resource overlaps" for pnp 00:08 in my dmesg, even though
AFAIK those have never caused any trouble.

Bisection identified this commit as the cause:
commit 999ed65ad12e374d7445fbc13f5a1d146ae4b0da
Author: Rene Herman <rene.herman@xxxxxxxxx>
Date: Fri Jul 25 19:44:47 2008 -0700
pnp: have quirk_system_pci_resources() include io resources

The PCI devices mentioned in the messages (1f.5 and 1f.6) are the ICH4
AC'97 audio controller and AC'97 (software) modem. At least sound works
fine _without_ this change; I don't really use the softmodem.
I'm not completely sure what pnp 00:08 is. Seems to have the "system"
driver.

Anyway, I wonder if this patch is really desirable as a general check.

It's not just a check, and not just general...

Generally, you need it -- if PnP grabs an I/O resource, PCI can no longer do so (making the driver fail) which is the same problem that quirk_system_pci_resources() upto that point solved for mem resources only.

And specifically, I definitely need it to not have my soundcard driver crap out due to PnPACPI grabbing a range that overlaps with its BAR.

I don't know why your 1f.5 and 1f.6 are grabbing the "motherboard I/O ports" 0x00-0xff (with your BIOS also advertising those ports through ACPI) but obviously, 78 messages are not something to put up with.

Bjorn might have something more to say about the general setup of things here but at this point and for now it might make most sense to just go ahead and do our doings without noting that we do. Ie, just delete the message...

Rene.