From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Date: Wed, 04 Jul 2012 13:00:56 +0000 Subject: Re: [PATCH] pwm-backlight: add regulator and GPIO support Message-Id: <20120704130056.GC30009@pengutronix.de> List-Id: References: <1340976167-27298-1-git-send-email-acourbot@nvidia.com> <20120704104840.GJ24458@pengutronix.de> <4FF43692.2040805@nvidia.com> In-Reply-To: <4FF43692.2040805-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alex Courbot Cc: Thierry Reding , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" On Wed, Jul 04, 2012 at 09:26:58PM +0900, Alex Courbot wrote: > Hi Sascha, > > On 07/04/2012 07:48 PM, Sascha Hauer wrote:>> + > >> + pb->power_reg = devm_regulator_get(&pdev->dev, "power"); > >> + if (IS_ERR(pb->power_reg)) > >> + return PTR_ERR(pb->power_reg); > > > > This looses several resources allocated earlier, like the enable gpio > > and the pwm. This is really bad here since I have no regulator specified > > and devm_regulator_get returns with -EPROBE_DEFER. Next time the core > > tries to probe the driver the driver bails out because the gpio and the > > pwm is already requested. > > That's very bad indeed. I assumed that the kernel would free > devm-allocated resources after probe returned -EPROBE_DEFER, It indeed does free devm allocated resources, but neither the gpio nor the pwm are devm allocated. Also please be aware that using a regulator in the pwm backlight will instantly break all existing users. That's hardly your fault though. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |