[PATCH] intel_idle: PCI quirk to prevent Lenovo Ideapad s10-3 boot hang

[Ike Panhc]

On 09/27/2010 06:24 PM, Ike Panhc wrote:
> From: Len Brown <len.brown at intel.com>
> 
> When the Lenovo Ideapad S10-3 is booted with HT enabled,
> it hits a boot hang in the intel_idle driver.
> 
> This occurs when entering ATM-C4 for the first time,
> unless BM_STS is first cleared.
> 
> acpi_idle doesn't see this because it first checks
> and clears BM_STS, but it would hit the same hang
> if that check were disabled.
> 
> http://bugs.meego.com/show_bug.cgi?id=7093
> BugLink: http://launchpad.net/bugs/634702
> 
> Signed-off-by: Len Brown <len.brown at intel.com>
> Signed-off-by: Ike Panhc <ike.pan at canonical.com>

After cherry-picked 6ce9cd from mainline kernel and let intel_idle built-in.
Maverick kernel boot and hang on Lenovo ideapad S10-3. Thanks for Len Brown who
has the same report and find the solution.

I have tried maverick-22.33 kernel and it boots failed on S10-3. After apply
this patch it boots fine.

This patch is available in the git repository at:
  git://kernel.ubuntu.com/ikepanhc/public.git lp634702