From mboxrd@z Thu Jan  1 00:00:00 1970
From: cw00.choi@samsung.com (Chanwoo Choi)
Date: Fri, 03 Apr 2015 08:39:13 +0900
Subject: [PATCH v7 1/9] arm64: dts: exynos: Add dts files for 64-bit
 Exynos5433 SoC
In-Reply-To: <20150402173558.GB30669@leverpostej>
References: <1426637856-3730-1-git-send-email-cw00.choi@samsung.com>
 <1426637856-3730-2-git-send-email-cw00.choi@samsung.com>
 <20150330160940.GA13731@leverpostej> <5519E2B6.2030905@samsung.com>
 <20150402173558.GB30669@leverpostej>
Message-ID: <551DD321.6030707@samsung.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 04/03/2015 02:35 AM, Mark Rutland wrote:
> On Tue, Mar 31, 2015 at 12:56:38AM +0100, Chanwoo Choi wrote:
>> Hi Mark,
>>
>> On 03/31/2015 01:09 AM, Mark Rutland wrote:
>>> Hi,
>>>
>>> On Wed, Mar 18, 2015 at 12:17:28AM +0000, Chanwoo Choi wrote:
>>>> This patch adds new Exynos5433 dtsi to support 64-bit Exynos5433 SoC based on
>>>> Octal core CPUs (quad Cortex-A57 and quad Cortex-A53). And Exynos5433 supports
>>>> PSCI (Power State Coordination Interface) v0.1.
>>>>
>>>> This patch includes following dt node to support Exynos5433 SoC:
>>>> 1. Octa core for big.LITTLE architecture
>>>> - Cortex-A53 LITTLE Quad-core
>>>> - Cortex-A57 big Quad-core
>>>> - Support PSCI v0.1
>>>
>>> Is CPU0 hotplug still broken, or has the FW been fixed?
>>
>> CPU0 hotplug is still not working.
>>
>>>
>>> I'm very worried about adding a DT that's known broken, especially when
>>> we have no idea as to if/when the FW will be fixed judging from prior
>>> replies.
>>
>> As I replied, I can not fix the FW because I don't have any code of FW.
> 
> Surely you are able to contact those who do?
> 
>> I don't have any solution to fix it on Linux kernel level.
>>
>> So, If you agree, I can add the comment of CPU0 hotplug issue on DT file.
> 
> I disagree. I do not want to add a DT that is known to be broken;
> especially when we have no idea how to fix it. It creates long-term
> maintenance pain for everyone, and marginal gain for few. A comment does
> nothing to aid the end-user.
> 
> So NAK to the PSCI node and PSCI enable method in this dts until we
> either have a working firmware, or a reasonable mechanism to handle the
> deficiency.

There is only CPU0 hotplug issue. Excpet CPU{1-7} are well working.
To fix this issue, we must need the help of firmware developer.
But, We never get the any help. Also, as I mentioned on previous mail,
all Exynos SoCs can not turn off the CPU0. I've never seen Exynos SoC
that CP0 hotplug is possible.

Thanks,
Chanwoo Choi