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Date: Mon, 18 Aug 2014 11:51:30 +0900
From: Sahara <keun-o.park@windriver.com>
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To: Andrew Morton <akpm@linux-foundation.org>, <kpark3469@gmail.com>
CC: <hpa@zytor.com>, <rafael.j.wysocki@intel.com>, <peterz@infradead.org>,
        <rusty@rustcorp.com.au>, <kirill.shutemov@linux.intel.com>,
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Subject: Re: [PATCH] earlyprintk: re-enable earlyprintk calling early_param
References: <1408011216-8621-1-git-send-email-kpark3469@gmail.com> <20140814133425.0677d072ff45bce8431baae1@linux-foundation.org>
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2014년 08월 15일 05:34, Andrew Morton 쓴 글:
> On Thu, 14 Aug 2014 19:13:36 +0900 kpark3469@gmail.com wrote:
>
>> From: Sahara <keun-o.park@windriver.com>
>>
>> Although there are many obs_kernel_param and its names are
>> earlyprintk and also EARLY_PRINTK is also enabled, we could not
>> see the early_printk output properly until now. This patch
>> considers earlycon as well as earlyprintk.
> Sorry, I just don't understand this description.
>
> What does the patch actually do?  What was the kernel behaviour without
> the patch and what is the kernel behaviour with the patch?
>
Without this patch,
- earlycon case -
if early_param("earlycon", ...) is defined and
case #1: if cmdline has "earlycon", then it satisfies the condition 
"(p->early && parameq(param, p->str))". You can see early_printk().
case #2: if cmdline has "console", then it satisfies the condition 
"strcmp(param, "console") == 0 && strcmp(p->str, "earlycon") == 0". You 
can see early_printk().

- earlyprintk case -
if early_param("earlyprintk", ...) is defined and
case #1: if cmdline has "earlyprintk", then it satisfies the condition 
"(p->early && parameq(param, p->str))". You can see early_printk().
case #2: if cmdline has "console", it does not satisfies the condition, 
because it only checks out "earlycon" only.

This patch fixes the case #2 problem of earlyprintk.

Thanks.

Best Regards,
Sahara.