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Message-ID: <8f252f5b-aca4-a96f-ac3b-1a8cd7551a2e@loongson.cn>
Date:   Wed, 21 Jun 2023 22:42:08 +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>
From:   Sui Jingfeng <suijingfeng@loongson.cn>
Organization: Loongson
In-Reply-To: <8f74f0962c8bab6c832919a5340667c54e1a7ddc.camel@pengutronix.de>
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On 2023/6/21 18:00, Lucas Stach wrote:
>> +static bool etnaviv_is_dma_coherent(struct device *dev)
>> +{
>> +	struct device_node *np;
>> +	bool coherent;
>> +
>> +	np = etnaviv_of_first_available_node();
>> +	if (np) {
>> +		coherent = of_dma_is_coherent(np);
>> +		of_node_put(np);
>> +	} else {
>> +		coherent = dev_is_dma_coherent(dev);
>> +	}
> This whole dance shouldn't be needed. We transfer the DMA capabilities
> from the first node to the virtual master device in the platform device
> case, so dev_is_dma_coherent(dev) should always return the right thing.
>
OK, I'm fine if this is OK on your platform.
>> +
>> +	return coherent;
>> +}
>> +

-- 
Jingfeng