From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Courbot Subject: Re: [PATCH 2/3] tegra: pwm-backlight: add tegra pwm-bl driver Date: Wed, 23 Jan 2013 19:29:16 +0900 Message-ID: <3208798.X7kqxH1FjQ@percival> References: <1358591420-7790-1-git-send-email-acourbot@nvidia.com> <1358591420-7790-3-git-send-email-acourbot@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Leela Krishna Amudala Cc: Thierry Reding , Stephen Warren , "linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Mark Zhang , "gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On Wednesday 23 January 2013 18:15:30 Leela Krishna Amudala wrote: > > + pwm_backlight_set_subdriver_data(dev, data); > > Here you are passing ventana_bl_data pointer as input and in the > pwm_backlight_get_subdriver_data() function you are assigning the > received driver data to backlight_device pointer. As both are two > different structures with different structure fields in it. There can > be a chance for a crash. That's because the following happens later in pwm_backlight_probe(): pb->subdriver_data = dev_get_drvdata(&pdev->dev); ... bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb, &pwm_backlight_ops, &props); ... platform_set_drvdata(pdev, bl); So from then on the result of dev_get_drvdata() is indeed an instance of backlight_device from which we can retrieve the subdriver data. I'm not really proud of this. But fortunately it seems like we are going to do things differently. Alex.