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[34.142.211.105]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3ac94794dd9sm19384883a91.12.2026.10.19.01.25.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Oct 2026 01:25:24 -0700 (PDT) Date: Mon, 19 Oct 2026 08:25:16 +0000 From: Pranjal Shrivastava To: Will Deacon Cc: iommu@lists.linux.dev, Joerg Roedel , Robin Murphy , Jason Gunthorpe , Mostafa Saleh , Nicolin Chen , Daniel Mentz , Ashish Mhetre , linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Radu Rendec , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , rafael@kernel.org, Danilo Krummrich , driver-core@lists.linux.dev Subject: Re: [PATCH v11 11/16] iommu/arm-smmu-v3: Add CMDQ_PROD_STOP_FLAG to gate CMDQ submissions Message-ID: References: <20260929034510.2023173-1-praan@google.com> <20260929034510.2023173-12-praan@google.com> Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Oct 07, 2026 at 03:08:01PM +0100, Will Deacon wrote: > On Tue, Sep 29, 2026 at 03:45:05AM +0000, Pranjal Shrivastava wrote: > > Introduce a new bit flag, CMDQ_PROD_STOP_FLAG (bit 30), in the command > > queue's producer index to safely gate command submissions during device > > suspension. > > > > The flag embeds the suspend state directly into the existing global state > > The flag is checked in the cmpxchg loop in arm_smmu_cmdq_issue_cmdlist(), > > which acts as a Point of Commitment, ensuring that no indices are > > reserved or committed once the SMMU begins suspending. > > I'm not familiar with the term "Point of Commitment". Is that something > you came up with? Without a general definition, I think I'd prefer to > avoid using it, especially as it sounds like something to do with the > Arm memory system (where we already have architectural terms such as > "Point of Coherency". > Ack. I'll re-word this to avoid confusion. Thanks, Praan