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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Aug 2025 05:11:40.3324 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 66b59cdb-8784-4321-6367-08dde13a60d2 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BL02EPF00029929.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB7759 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250821_221152_427396_12588451 X-CRM114-Status: GOOD ( 17.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Aug 21, 2025 at 03:37:04PM -0300, Jason Gunthorpe wrote: > On Thu, Aug 21, 2025 at 08:22:06AM -0700, Nicolin Chen wrote: > > I should have pasted the full piece: > > drivers/gpu/drm/tegra/drm.c-960- /* > > drivers/gpu/drm/tegra/drm.c:961: * If the host1x client is already attached to an IOMMU domain that is > > drivers/gpu/drm/tegra/drm.c-962- * not the shared IOMMU domain, don't try to attach it to a different > > drivers/gpu/drm/tegra/drm.c-963- * domain. This allows using the IOMMU-backed DMA API. > > drivers/gpu/drm/tegra/drm.c-964- */ > > drivers/gpu/drm/tegra/drm.c-965- if (domain && domain->type != IOMMU_DOMAIN_IDENTITY && > > drivers/gpu/drm/tegra/drm.c-966- domain != tegra->domain) > > > > So, the check is two-fold: > > 1) is attached > > 2) is the shared IOMMU domain (tegra->domain?) > > Yea > > iommu_is_domain_currently_attached(dev, tegra->domain) Ah, yea. > > Overall, I feel this would be a big project yet arguably for a low > > reward.. > > Indeed, we can drop a FIXME comment there and leave it as the last > user or something perhaps I see. We could keep it in the library but discourage new callers. I will start with the internal cleanup as we discussed, as a part of this PCI reset series. Then, I will try adding those new helper functions that we've listed here, as a separate series. Thanks Nicolin