From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 18 Aug 2021 11:43:05 +0530 From: Srivatsa Vaddagiri Subject: Re: [virtio-dev] Re: [PATCH v1] virtio-mmio: Specify wait needed in driver during reset Message-ID: <20210818061305.GE9207@quicinc.com> Reply-To: Srivatsa Vaddagiri References: <20210816063550.GD5604@quicinc.com> <20210816074558-mutt-send-email-mst@kernel.org> <20210817034312-mutt-send-email-mst@kernel.org> <20210817100333.GA9207@quicinc.com> <20210818051544.GC9207@quicinc.com> <20210818055102.GD9207@quicinc.com> MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline To: Jason Wang Cc: "Michael S. Tsirkin" , Srivatsa Vaddagiri , Cornelia Huck , "virtio-dev@lists.oasis-open.org" , Trilok Soni , Pratik Patel List-ID: * Jason Wang [2021-08-18 14:04:04]: > > Fine let me take a stab at the next version which will have this: > > > > * Introduce a status bit for device to indicate "reset in progress". This could > > be adopted by other transports also (for ex PCI). > > I may miss something discussion but any reason that the current > VIRTIO_MMIO_STATUS is not sufficient? I think Mike suggested we specify what device would return while reset is in progress, rather than any arbitrary non-zero value: https://lists.oasis-open.org/archives/virtio-dev/202108/msg00070.html > > * For v3 MMIO devices, driver, after initiating reset, should wait until > > status = 0 or device indicates "failure". What the driver does when it sees > > failure can be implementation defined (it can give up or try reset few more > > times) > > Yes, but let's wait a little bit to see if it is agreed by others. Sure. Mike, Do you suggest we add this as well for v3 device? "after writing 0 to Status and before reading any fields, the driver MUST read Status and wait for a read to return 0 or indicate failure" - vatsa -- Qualcomm Innovation Center, Inc. is submitting the attached "feedback" as a non-member to the virtio-dev mailing list for consideration and inclusion.