Re: [PATCH 2/2] pinctrl: baytrail: Serialize all register access

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Oct 30, 2015 at 12:48:38PM -0200, Lucas De Marchi wrote:
> Hi Mika and Linus,
> 
> CC'ing Greg.
> 
> On Tue, Aug 4, 2015 at 9:03 AM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> > There is a hardware issue in Intel Baytrail where concurrent GPIO register
> > access might result reads of 0xffffffff and writes might get dropped
> > completely.
> >
> > Prevent this from happening by taking the serializing lock in all places
> > where it is possible that more than one thread might be accessing the
> > hardware concurrently.
> >
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> 
> Now that this is on 4.2, can we get it on stable branches?  I was
> hitting this bug for some time on MinnowBoard Max and this week I had
> some time to take a look on how to fix it. Good timing, it had already
> been fixed. Applying this patch the issue is gone on top of 4.1.12.
> 
> I'm using these patches from Linus Torvalds' tree:
> 39ce815 pinctrl: baytrail: Serialize all register access
> 78e1c89 pinctrl: baytrail: Use raw_spinlock for locking
> 
> 
> The ones to Cherryview could be sent too but I couldn't test them.
> 
> Leaving the patch below for reference.

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>