linux-kernel - Re: [PATCH 1/9] [media] s5p-jpeg: Reset the Codec before doing a soft reset

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Date:   Tue, 13 Jun 2017 20:46:44 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Thierry Escande <thierry.escande@...labora.com>,
        Andrzej Pietrasiewicz <andrzej.p@...sung.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/9] [media] s5p-jpeg: Reset the Codec before doing a soft
 reset

Hi Thierry,

On 06/07/2017 02:34 PM, Thierry Escande wrote:
> Hi Jacek,
> 
> On 02/06/2017 21:50, Jacek Anaszewski wrote:
>> Hi Thierry,
>>
>> On 06/02/2017 06:02 PM, Thierry Escande wrote:
>>> From: Abhilash Kesavan <a.kesavan@...sung.com>
>>>
>>> This patch resets the encoding and decoding register bits before doing a
>>> soft reset.
>>>
>>> Signed-off-by: Tony K Nadackal <tony.kn@...sung.com>
>>> Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
>>> ---
>>>   drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c | 4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
>>> b/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
>>> index a1d823a..9ad8f6d 100644
>>> --- a/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
>>> +++ b/drivers/media/platform/s5p-jpeg/jpeg-hw-exynos4.c
>>> @@ -21,6 +21,10 @@ void exynos4_jpeg_sw_reset(void __iomem *base)
>>>       unsigned int reg;
>>>         reg = readl(base + EXYNOS4_JPEG_CNTL_REG);
>>> +    writel(reg & ~(EXYNOS4_DEC_MODE | EXYNOS4_ENC_MODE),
>>> +           base + EXYNOS4_JPEG_CNTL_REG);
>>
>> Why is it required? It would be nice if commit message explained that.
> 
> Unfortunately the bug entry in the ChromeOS issue tracker does not
> mention more information about that and the patch author is no more
> reachable on that email address.
> 
> So unless someone else knows the answer I won't be able to give more
> explanation in the commit message...

Unfortunately I don't have longer access to the hardware and
can't test these changes. Have you tested them, or just cherry-picked
from the bug tracker?

-- 
Best regards,
Jacek Anaszewski