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Tue, 02 Nov 2021 23:37:47 -0700 (PDT) Received: from localhost ([106.201.113.61]) by smtp.gmail.com with ESMTPSA id oa4sm930068pjb.13.2021.11.02.23.37.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Nov 2021 23:37:47 -0700 (PDT) Date: Wed, 3 Nov 2021 12:07:45 +0530 From: Viresh Kumar To: "Chen, Conghui" Subject: Re: [PATCH 1/2] i2c: virtio: disable timeout handling Message-ID: <20211103063745.utpphthou4angs4s@vireshk-i7> References: <8e182ea8-5016-fa78-3d77-eefba7d58612@intel.com> <20211020064128.y2bjsbdmpojn7pjo@vireshk-i7> <01d9c992-28cc-6644-1e82-929fc46f91b4@intel.com> <20211020105554.GB9985@axis.com> <20211020110316.4x7tnxonswjuuoiw@vireshk-i7> <20211029122450.GB24060@axis.com> <8592a48d-0131-86bf-586a-d33e7989e523@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716-391-311a52 Cc: Greg KH , Vincent Whitchurch , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , Wolfram Sang , kernel , "linux-i2c@vger.kernel.org" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On 03-11-21, 06:18, Chen, Conghui wrote: > >>> Over the long term, I think the backend should provide that timeout > >>> value and guarantee that its processing time should not exceed that > >>> value. > >> If you mean that the spec should be changed to allow the virtio driver > >> to be able to program a certain timeout for I2C transactions in the > >> virtio device, yes, that does sound reasonable. > > > > > >Due to changes in my work, I will pass my virtio-i2c maintenance to Conghui. > > > >She may work on this in the future. > > > > I'll try to update the spec first. I don't think the spec should be changed for timeout. Timeout-interval here isn't the property of just the host firmware/kernel, but the entire setup plays a role here. Host have its own timeframe to take care of things (I think HZ should really be enough for that, since kernel can manage it for busses normally with just that). Then comes the virtualization, context switches, guest OS, backend, etc, which add to this delay. All this is not part of the virtio protocol and so shouldn't be made part of it. -- viresh _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization