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Message-ID: <be525b88-4af2-eb5f-48ec-64b8d3198516@loongson.cn>
Date:   Sun, 25 Jun 2023 00:10:42 +0800
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Subject: Re: [PATCH v10 07/11] drm/etnaviv: Add support for the dma coherent
 device
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To:     Lucas Stach <l.stach@pengutronix.de>,
        Sui Jingfeng <18949883232@163.com>,
        Russell King <linux+etnaviv@armlinux.org.uk>,
        Christian Gmeiner <christian.gmeiner@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        etnaviv@lists.freedesktop.org,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Bjorn Helgaas <bhelgaas@google.com>
References: <20230620094716.2231414-1-18949883232@163.com>
 <20230620094716.2231414-8-18949883232@163.com>
 <8f74f0962c8bab6c832919a5340667c54e1a7ddc.camel@pengutronix.de>
 <66fc74ae-299c-a5de-9cfb-07ae24fb3f07@loongson.cn>
 <8212078bd56c54ce508205eae0ed0b69e78d4c38.camel@pengutronix.de>
 <fd5dd250-b01e-fd00-1419-88398cb13347@loongson.cn>
 <62bf84f19318c54c50f154e1eb64a179fb2389ce.camel@pengutronix.de>
From:   Sui Jingfeng <suijingfeng@loongson.cn>
Organization: Loongson
In-Reply-To: <62bf84f19318c54c50f154e1eb64a179fb2389ce.camel@pengutronix.de>
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Hi,

On 2023/6/22 01:45, Lucas Stach wrote:
>> Again,
>>
>> this is user-space things!
>>
>> this is user-space things!
>>
>> this is user-space things!
>>
>> I have explained several times.
>>
>> made the decision for the user-space program is wrong.
>>
> This mode of communication isn't helpful. Please stop it.
>
> As I tried to explain to you multiple times: if userspace can break
> coherency by selecting the wrong mapping type then this is something
> the kernel should prevent.
>
This is still a user-space things.

While my point is that we want to prevent it at userspace.

Please don't forget that sometime a user or a programmer want a wrong thing.
  
Either because of the need of debugging itself or due to the curiosity of

what it would happen if we doing something wrong.

Sometimes, the wrong rendering may more interesting.


The most important thing is that my patch is trying to increase the 
flexibility,

and to increase the possibility. While you idea is to doing the reverse.


-- 
Jingfeng