International Business Machines Corporation

International Business Corporation

Robert Paul Stelzer

James Anthony Pafumi

Wei Kuo

Mark Richard Nutter

John Paul Harvey

Sidney James Manning

Dac D Nguyen

Paul Joseph Milot

Truc Duy Nguyen

Timothy Howard White

According to one embodiment of the present invention, the illustrative embodiments provide a computer implemented method, apparatus, and computer program product for configuring devices. Device information for a plurality of devices is retrieved from an object data manager. A determination is made as to whether a keyboard-video-mouse environment exists. If a keyboard-video-mouse environment does not exist, each device in a plurality of devices is configured to either an available state or a defined state. If a keyboard-video-mouse environment exists, each device in the plurality of devices is configured to the available state. A list of all enumerated devices is requested and a determination is made as to whether a particular device is in the list of enumerated devices. If the particular device is not in the list of enumerated devices, a pseudo device is added to the list to form a modified list of all enumerated devices.

USB devices pre-configuration for KVM switch

A method, apparatus and computer instructions for storing data relating to the switch in a context switch history containing a number of prior context switches occurring prior to a current context. The storing of data occurs in response to a change in context for a direct memory access resource. Portions of the direct memory access chain of requests are freed using the context switch history to form freed portions, wherein the freed portions are reused for requests.

Method and apparatus for managing context switches using a context switch history table

A method, apparatus, and computer instructions for managing direct memory access transfers. Monitoring is performed for an event to pass ownership of a direct memory access resource to a new thread. A buffer of the new thread is added by an operating system component to the end of a direct memory access chain of requests from the current thread. The addition of this buffer to the end of a direct memory access chain provides an anchor point for the new thread to add additional requests for the direct memory access resource.

Method and apparatus for efficient sharing of DMA resource

A method, apparatus, and computer implemented instructions for managing a set of memory resources used to store texture objects in a data processing system. A texture manager allocates memory to a current texture object in a set of memory resources. A stored texture object, handled by the texture manager, is selectively removed in response to an inability to allocate sufficient memory to the current texture object. The allocating and selectively removing steps are repeated until the current texture object is allocated sufficient memory. The repeating step is halted in response to an absence of any stored texture objects, handled by a texture manager, being present in the first memory resource. Stored texture objects, handled by another texture manager, are selectively removed in response to an inability to allocate sufficient memory to the current texture object. Memory is allocated in the set of memory resources to the current texture object in response to selectively removing stored texture objects.

Method and apparatus for managing texture memory in a data processing system

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.

Efficient adapter context switching

A computer system having a graphics display with texture management employs a graphics adapter with texture memory. The graphics adapter is 'virtualized' by the operating system. When making a graphics context switch, the state of the graphics adapter including texture memory is saved. Threads are used to allow rapid and frequent context switches. A graphics process that will use texture memory in the adapter reserves a thread, for use during a graphics context switch. The thread calls into the operating system where it is blocked until a graphics context switch is initiated. At that time, the thread is unblocked to do texture management, such as saving of texture memory. During the save portion of the graphics context switch the graphics driver saves the current hardware state of the adapter, and the special purpose texture thread is unblocked to allow texture memory to be processed, and saves texture memory and calls back into the driver where it is blocked. During the restore portion of the graphics context switch the driver restores the state of the adapter to that of another graphics process, except for texture memory. The special purpose texture thread associated with the new graphics process is unblocked, passed an indication that a restore operation is in progress, and restores textures as required and calls back into the driver where it is blocked in the kernel. The driver completes the context switch and the graphics process is dispatched.

Growing community of inventors

Austin, TX, United States of America

Robert Paul Stelzer