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Subject: Re: [PATCH 1/4] driver core: Use subdir-ccflags-* to inherit debug
 flag
To:     Greg KH <gregkh@linuxfoundation.org>
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References: <1612518255-23052-1-git-send-email-yangyicong@hisilicon.com>
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 <YB0Vk6ERJ3lFc3WD@kroah.com>
From:   Yicong Yang <yangyicong@hisilicon.com>
Message-ID: <08017751-a1be-ea07-50de-73d14ab6d57e@hisilicon.com>
Date:   Mon, 8 Feb 2021 18:44:52 +0800
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Hi Greg,

On 2021/2/5 17:53, Greg KH wrote:
> On Fri, Feb 05, 2021 at 05:44:12PM +0800, Yicong Yang wrote:
>> From: Junhao He <hejunhao2@hisilicon.com>
>>
>> Use subdir-ccflags-* instead of ccflags-* to inherit the debug
>> settings from Kconfig when traversing subdirectories.
> 
> That says what you do, but not _why_ you are doing it.

i'll illustrate the reason and reword the commit.

> 
> What does this offer in benefit of the existing way?  What is it fixing?
> Why do this "churn"?

currently we have added ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG in the Makefile
of driver/base and driver/base/power, but not in the subdirectory
driver/base/firmware_loader. we cannot turn the debug on for subdirectory
firmware_loader if we config DEBUG_DRIVER and there is no kconfig option
for the it.

as there is no other debug config in the subdirectory of driver/base,
CONFIG_DEBUG_DRIVER may also mean turn on the debug in the subdirectories, so use
subdir-ccflags-* instead for the -DDEBUG will allow us to enable debug for all
the subdirectories.

Thanks,
Yicong

> 
> thanks,
> 
> greg k-h
> 
> .
>