linux-kernel - Re: 2.6.35-rc3 regression: IBM Maia system is unbootable [ACPI related?]

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Tue, 29 Jun 2010 11:49:08 -0500
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Len Brown <lenb@...nel.org>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: 2.6.35-rc3 regression: IBM Maia system is unbootable [ACPI
 related?]

On Mon, 2010-06-28 at 23:49 -0400, Len Brown wrote:
> From: Len Brown <len.brown@...el.com>
> Subject: [PATCH] ACPI: handle systems which asynchoronously enable ACPI mode
> 
> Folklore suggested that such systems existed
> in the pre-history of ACPI.
> 
> However, we removed the SCI_EN polling loop from
> acpi_hw_set_mode() in b430acbd7c4b919886fa7fd92eeb7a695f1940d3
> because it delayed resume by 3 seconds on boxes
> that refused to set SCI_EN.
> 
> Matthew removed the call to acpi_enable() from
> the suspend resume path.
> 
> James found a modern system that still needs to be polled
> upon boot.
> 
> So here we restore the workaround, except that we
> put it in acpi_enable() rather than the low level
> acpi_hw_set_mode().
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=16271
> 
> Signed-off-by: Len Brown <len.brown@...el.com>
> ---
> 
> James, What does the IBM system see with this patch?

The output is this:

[    0.084088] ACPI: Core revision 20100428
[    0.119451] ACPI Warning: Platform took > 100 usec to enter ACPI mode (20100428/evxfevnt-106)
[    0.128231] Setting APIC routing to physical flat

So it's very fast ... actually it's behaving like there's some caching
issue and it needs two reads to return the correct value

James


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/