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Message-ID: <a4738b42-b297-766c-56bf-94a91bc82767@cmss.chinamobile.com>
Date: Fri, 10 Apr 2020 17:15:39 +0800
From: Tang Bin <tangbin@...s.chinamobile.com>
To: Markus Elfring <Markus.Elfring@....de>, linux-usb@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org
Cc: Li Yang <leoyang.li@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Felipe Balbi <balbi@...nel.org>,
Shengju Zhang <zhangshengju@...s.chinamobile.com>,
LKML <linux-kernel@...r.kernel.org>,
kernel-janitors@...r.kernel.org
Subject: Re: usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()
Hi Markus:
On 2020/4/10 16:30, Markus Elfring wrote:
>> Hardware experiments show that the negative return value is not just "-EPROBE_DEFER".
> How much will this specific error code influence our understanding
> of the discussed software situation?
>
From my superficial knowledge, I think we should not think about it
too complicated. The return value is just zero or negative, and for
these negative return value, such as
"-ENODEV"、"-ENXIO"、"-ENOENT"、“EPROBE_DEFER”,may be the same
effect。But“-EPROBE_DEFER”has another importment function: Driver
requested deferred probing,which is used in cases where the dependency
resource is not ready during the driver initialization process.
>>>> + ret = udc_controller->irq ? : -ENODEV;
>>> Will it be clearer to specify values for all cases in such a conditional operator
>>> (instead of leaving one case empty)?
>> I don't know what you mean of "instead of leaving one case empty".
> I suggest to reconsider also the proposed specification “… ? : …”.
What you mean is the way I'm written?
I have provided two ways of patching, both functional can be verified on
hardware.
Thanks for your patience.
Tang Bin
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