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[165.204.72.6]) by smtp.gmail.com with ESMTPSA id t15-20020a7bc3cf000000b00402be2666bcsm16448614wmj.6.2023.09.12.07.46.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Sep 2023 07:46:32 -0700 (PDT) Message-ID: <95797f3d-65bf-1bd9-9e19-6de42605cfe3@gmail.com> Date: Tue, 12 Sep 2023 16:46:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH 3/9] dma-heap: Provide accessors so that in-kernel drivers can allocate dmabufs from specific heaps Content-Language: en-US To: =?UTF-8?B?WW9uZyBXdSAo5ZC05YuHKQ==?= , "jstultz@google.com" Cc: "sumit.semwal@linaro.org" , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , "linux-mediatek@lists.infradead.org" , "linaro-mm-sig@lists.linaro.org" , "linux-media@vger.kernel.org" , "devicetree@vger.kernel.org" , =?UTF-8?B?SmlhbmppYW8gWmVuZyAo5pu+5YGl5aejKQ==?= , =?UTF-8?B?S3VvaG9uZyBXYW5nICjnjovlnIvptLsp?= , "Brian.Starkey@arm.com" , "conor+dt@kernel.org" , "benjamin.gaignard@collabora.com" , "tjmercier@google.com" , "krzysztof.kozlowski+dt@linaro.org" , "dri-devel@lists.freedesktop.org" , "matthias.bgg@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "angelogioacchino.delregno@collabora.com" References: <20230911023038.30649-1-yong.wu@mediatek.com> <20230911023038.30649-4-yong.wu@mediatek.com> <803846bc-fd1d-d2ec-2855-456af22c82f8@amd.com> <23e71d1f-08c1-3834-5b1f-2b5714c7bfaa@gmail.com> <255ae6b9ac1b6bea9262069747824b8461475e70.camel@mediatek.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= In-Reply-To: <255ae6b9ac1b6bea9262069747824b8461475e70.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 12.09.23 um 10:52 schrieb Yong Wu (吴勇): > [SNIP] >> But what we should try to avoid is that newly merged drivers provide >> both a driver specific UAPI and DMA-heaps. The justification that >> this >> makes it easier to transit userspace to the new UAPI doesn't really >> count. >> >> That would be adding UAPI already with a plan to deprecate it and >> that >> is most likely not helpful considering that UAPI must be supported >> forever as soon as it is upstream. > Sorry, I didn't understand this. I think we have not change the UAPI. > Which code are you referring to? Well, what do you need this for if not a new UAPI? My assumption here is that you need to export the DMA-heap allocation function so that you can server an UAPI in your new driver. Or what else is that good for? As far as I understand you try to upstream your new vcodec driver. So while this change here seems to be a good idea to clean up existing drivers it doesn't look like a good idea for a newly created driver. Regards, Christian. >>> So I think this patch is a little confusing in this series, as I >> don't >>> see much of it actually being used here (though forgive me if I'm >>> missing it). >>> >>> Instead, It seems it get used in a separate patch series here: >>> >> https://lore.kernel.org/all/20230911125936.10648-1-yunfei.dong@mediatek.com/ >> >> Please try to avoid stuff like that it is really confusing and eats >> reviewers time. > My fault, I thought dma-buf and media belonged to the different tree, > so I send them separately. The cover letter just said "The consumers of > the new heap and new interface are our codecs and DRM, which will be > sent upstream soon", and there was no vcodec link at that time. > > In the next version, we will put the first three patches into the > vcodec patchset. > > Thanks. >