Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 0/2] Subject: [PATCH 0/2] clocksource: exynos_mct: Clear
 timer interrupt when shutting down
To:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Stuart Menefy <stuart.menefy@mathembedded.com>,
        linux-samsung-soc@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Kukjin Kim <kgene@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
References: <CGME20190210225147epcas3p4cedebfc5692274bc6135ceabbcf2642d@epcas3p4.samsung.com>
 <20190210225114.20110-1-stuart.menefy@mathembedded.com>
 <e22c175a-d88a-81a7-9faa-42bb4fe09a22@samsung.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
Message-ID: <e3637f0f-1e72-db3a-f744-ade0e878cfc5@linaro.org>
Date:   Mon, 11 Feb 2019 12:23:20 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.4.0
MIME-Version: 1.0
In-Reply-To: <e22c175a-d88a-81a7-9faa-42bb4fe09a22@samsung.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 11/02/2019 08:14, Marek Szyprowski wrote:
> Hi Stuart
> 
> On 2019-02-10 23:51, Stuart Menefy wrote:
>> When debugging suspend problems on Exynos 5260, I had a large number
>> of debugging prints going to the serial port after interrupts
>> had been disabled but before the timer interrupt was shutdown. This
>> was long enough for a timer tick to occur, but as interrupts were
>> disabled the ISR didn't run, and so the interrupt wasn't cleared.
>> Later when the timer was shutdown the interrupt was left asserted and
>> so the wfi at the heart of the suspend code didn't wait, causing
>> the suspend to fail.
>>
>> Currently the code which stops the timer when it is on one-shot mode
>> and the interrupt occurs is in exynos4_mct_tick_clear(), meaning if we
>> called this from the shutdown code exynos4_mct_tick_stop() could be
>> called twice. So first restructure the existing code, so the check for
>> one-shot mode and stopping the timer is moved to the ISR, leaving
>> exynos4_mct_tick_clear() just clearing the interrupt flag.
>>
>> Once this has been done simply call exynos4_mct_tick_clear() from
>> set_state_shutdown().
> 
> This also fixes mysterious suspend failures on Odroid XU3/XU4/HC1 :)
> 
> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Applied. Shall I add the stable@ tag?


-- 
 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog