Date: Wed, 15 Aug 2012 11:50:01 -0300
From: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        torvalds@linux-foundation.org, akpm@linux-foundation.org,
        alan@lxorguk.ukuu.org.uk, Colin Cross <ccross@android.com>,
        Barry Song <bs14@csr.com>, Catalin Marinas <catalin.marinas@arm.com>,
        Ido Yariv <ido@wizery.com>, Daniel Drake <dsd@laptop.org>,
        Will Deacon <will.deacon@arm.com>,
        Russell King <rmk+kernel@arm.linux.org.uk>
Subject: Re: [ 07/44] ARM: 7477/1: vfp: Always save VFP state in
 vfp_pm_suspend on UP
Message-ID: <20120815145000.GA3323@herton-Z68MA-D2H-B3>
References: <20120813220142.113186818@linuxfoundation.org>
 <20120813220142.801309366@linuxfoundation.org>
 <20120814200110.GE5277@herton-Z68MA-D2H-B3>
 <20120815140541.GB22871@kroah.com>
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On Wed, Aug 15, 2012 at 07:05:41AM -0700, Greg Kroah-Hartman wrote:
> On Tue, Aug 14, 2012 at 05:01:11PM -0300, Herton Ronaldo Krzesinski wrote:
> > On Mon, Aug 13, 2012 at 03:02:14PM -0700, Greg Kroah-Hartman wrote:
> > > From: Greg KH <gregkh@linuxfoundation.org>
> > > 
> > [...]
> > > --- a/arch/arm/vfp/vfpmodule.c
> > > +++ b/arch/arm/vfp/vfpmodule.c
> > > @@ -412,6 +412,12 @@ static int vfp_pm_suspend(void)
> > >  
> > >  		/* disable, just in case */
> > >  		fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
> > > +	} else if (vfp_current_hw_state[ti->cpu]) {
> > > +#ifndef CONFIG_SMP
> > > +		fmxr(FPEXC, fpexc | FPEXC_EN);
> > > +		vfp_save_state(vfp_current_hw_state[ti->cpu], fpexc);
> > > +		fmxr(FPEXC, fpexc);
> > > +#endif
> > 
> > This fails to build on 3.0:
> > 
> > linux-stable/arch/arm/vfp/vfpmodule.c: In function 'vfp_pm_suspend':
> > linux-stable/arch/arm/vfp/vfpmodule.c:415:13: error: 'vfp_current_hw_state' undeclared (first use in this function)
> > linux-stable/arch/arm/vfp/vfpmodule.c:415:13: note: each undeclared identifier is reported only once for each function it appears in
> > make[3]: *** [arch/arm/vfp/vfpmodule.o] Error 1
> > 
> > In 3.0, vfp_current_hw_state was still named last_VFP_context, so I
> > think just renaming should be enough to fix this.
> 
> I'll remove the patch as it probably just shouldn't be there, right?  If
> you think it should be in 3.0-stable, can you please send me a fixed up
> patch that you have tested that it at least builds properly?

I'm not intimate with this ARM code, so I think someone else in Cc can
answer better, I just saw it doesn't build with 3.0. If the same problem
affects 3.0, then the change should be backported renaming
vfp_current_hw_state to last_VFP_context. It seems the same code was
there with vfp_current_hw_state still named as last_VFP_context, so
looks like 3.0 would be affected as well.

Also I noted that because the same naming, 3.0 didn't got commit
a84b895a2348f0dbff31b71ddf954f70a6cde368 ("ARM: 7476/1: vfp: only clear
vfp state for current cpu in vfp_pm_suspend") as the patch would fail to
apply on 3.0 code base, while 3.4.9 and 3.5.2 have it.

I assume someone who did these commits or know it/are affected can take
a look and if needed backport them to 3.0?

> 
> thanks,
> 
> greg k-h
> 

-- 
[]'s
Herton
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