Revert UBUNTU Fix ARM VFP state corruption due to preemption

[Stefan Stefanov]

I have the problem on iMX31 platform running 2.6.22.6 PREEMPT.
I did not notice that PREEMPT is off for your kernels.

Anyway thanks a lot for the response.

Best regards,
Stefan.

-----Original Message-----
From: Amit Kucheria [mailto:amit.kucheria at verdurent.com] On Behalf Of Amit Kucheria
Sent: Monday, 25 May 2009 7:56 PM
To: Stefan Stefanov
Cc: kernel-team at lists.ubuntu.com
Subject: Re: Revert UBUNTU Fix ARM VFP state corruption due to preemption

On Mon, May 25, 2009 at 02:19:24PM +0930, Stefan Stefanov wrote:
> Hi kernel-team,
> 
> I have a similar problem to that described in "UBUNTU: Fix ARM VFP state corruption due to preemption".
> In my case the problem is to take an IRQ (causing preemtion) just before saving the last VFP context - VSTM     r4!,{d0-d15} in vfphw.S
> During the context switch the VFP is disabled via call to vfp_notifier() via atomic_notifier_call_chain(). That in turn causes a wrong VFP context to be saved in the original thread_info.
> 
> So I was wondering what is the reason to revert that patch?

What platform are you seeing this problem on?
It is unlikely that you are seeing the same problem since it is only
turned on in PREEMPTible kernels.

The reason for reverting the patch is in the commit message - it was
only meant for PREEMPT kernels. Since our kernels turn off PREEMPT, that
patch isn't necessary.

Regards,
Amit
-- 
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Amit Kucheria, Kernel Engineer || amit.kucheria at canonical.com
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