International Business Machines Corporation

Timothy Howard White

James Anthony Pafumi

Sidney James Manning

Robert Paul Stelzer

A method and system for controlling access to an adapter, such as a graphics adapter, are disclosed. The method includes querying an adapter lock with a first thread. Thereafter, responsive to determining that the lock indicates the first thread does not have access to the adapter, a sequence to obtain access to the adapter is initiated where the sequence includes writing the adapter context corresponding to the first thread. The, sequence may include a ring 3 to ring 0 transition. The method also includes, in response to determining that the lock indicates the first thread has access to the adapter, communicating to the adapter with the first thread without invoking the sequence to obtain access to the adapter. In one embodiment, querying the adapter lock includes writing a first word of the adapter lock using an atomic operation. The method may further include writing a set of command buffers with the first thread and, responsive to determining that the first has access to the adapter, transferring the commands buffers to the adapter. In one embodiment, the sequence to obtain access to the adapter includes the first thread obtaining ownership of a mutex lock prior to updating the adapter context. The sequence to obtain access to the adapter may include updating the adapter lock status to indicate the first thread having access to the adapter.

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Austin, TX, United States of America

Timothy Howard White