Re: [PATCH] pwm-backlight: add regulator and GPIO support

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:>> +

quoted

quoted

+	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

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