From: thierry.reding@gmail•com (Thierry Reding)
To: linux-arm-kernel@lists•infradead.org
Subject: pwm-backlight: 3.13-rc1 regression for old arm machine
Date: Tue, 17 Dec 2013 10:57:00 +0100 [thread overview]
Message-ID: <20131217095658.GD13823@ulmo.nvidia.com> (raw)
In-Reply-To: <87r49c6bea.fsf@free.fr>
On Mon, Dec 16, 2013 at 04:52:45PM +0100, Robert Jarzmik wrote:
> Hi Thierry,
Hi Robert,
Please always Cc the linux-pwm mailing list for PWM related questions.
I've done that now.
> Since recently, and probable since last Linus's merge of PWM tree (Merge tag
> 'pwm/for-3.13-rc1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm), my
> platform has its backlight broken.
>
> The particularity of my platform:
> - arch/arm/mach-pxa/mioa701.c
> - no device tree
> - no power supply regulator for backlight
> - backlight controlled by a PWM
> - kernel message :
> [ 1.495480] platform pwm-backlight: Driver pwm-backlight requests probe deferral
>
> I think other "old" platforms will suffer from this. Do you have a
> recommendation ?
I hadn't anticipated that =(. In fact I had been holding this patch back
for a release cycle because I was waiting for a specific regulator patch
to land which provides a dummy regulator if one wasn't specified. It
seems that that patch only works when booting from DT, though.
The correct way to fix this would be to provide a lookup table with the
dummy regulator in the board file. I've attached a patch (compile-tested
only) that might work.
If it does, please let me know and, if nobody else volunteers, I'll see
if I can come up with a set of patches to fix this for any other boards
that have the same issue.
Thierry
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next prev parent reply other threads:[~2013-12-17 9:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 15:52 pwm-backlight: 3.13-rc1 regression for old arm machine Robert Jarzmik
2013-12-17 9:57 ` Thierry Reding [this message]
2013-12-17 18:31 ` Robert Jarzmik
2013-12-20 9:47 ` Thierry Reding
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