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Date: Sat, 14 Oct 2017 02:25:48 +0800
From: jeffy <jeffy.chen@rock-chips.com>
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Subject: Re: [RESEND PATCH 1/2] spi: rockchip: Convert to late and early system
 PM callbacks
References: <20171013104138.3216-1-jeffy.chen@rock-chips.com> <20171013104138.3216-2-jeffy.chen@rock-chips.com> <CAD=FV=X6pkaY3t=ceh3QEUws+_gqRGMN9zveW0fXR1noF1T6ew@mail.gmail.com> <20171013155120.GA137489@google.com> <20171013164235.thgqha7sl5tdptwv@sirena.co.uk> <59E103B0.8060705@rock-chips.com>
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On 10/14/2017 02:19 AM, jeffy wrote:
>
>
> it looks like the suspend sequence depends on the dt node sequence, and
> we are putting display-subsystem dt node above spi dt node, so it would
> be earlier in the device list, then got suspended later than spi device.
>
> the pwm backlight and cros_ec_spi pwm are very interesting, not only
> about suspend dependency... if we unbind cros_ec_spi pwm, the pwm
> backlight would still hold a reference to it, and crash the kernel later.

or maybe we should move device_pm_add() from device_add() to driver_bound()?