VIRTUALIZING A POWERED DOWN INPUT/OUTPUT DEVICE

• US 20110153872A1
• Filed: 11/09/2010
• Published: 06/23/2011
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Siddhartha Nath
• Original Assignee: Siddhartha Nath
• Inventors: Nath, Siddhartha
• Granted Patent: US 8,959,253 B2
• Time in Patent Office: Days
• US Class Current: 710/10
• CPC Class Codes: G06F 1/3206 Monitoring of events, devices or parameters that trigger a change in power modality
• CPC Class Codes: G06F 9/4411 Configuring for operating with peripheral devices; Loading of device drivers
• CPC Class Codes: G06F 9/4418 Suspend and resume; Hibernate and awake
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/50 Allocation of resources, e.g. of the central processing unit [CPU]

Abstract

Embodiments of systems, apparatuses, and methods for virtualizing a powered-down input/output device are disclosed. In one embodiment, an apparatus includes a storage location and a decoder. The storage location is to store an indication that an input/output device is inaccessible. The decoder is to decode a configuration transaction directed to the input/output device and redirect the configuration transaction to an other target if the contents of the first storage location indicate that the input/output device is inaccessible.

Claims

1. An apparatus comprising:

a first storage location to store an indication that an input/output device is inaccessible;

a decoder to decode a configuration transaction directed to the input/output device and redirect the configuration transaction to an other target if the contents of the first storage location indicate that the input/output device is inaccessible.

2. The apparatus of claim 1, wherein the other target is a memory region.

3. The apparatus of claim 2, further comprising a second storage location to store a base address of the memory region.

4. The apparatus of claim 1, wherein the other target is an other input/output device.

5. The apparatus of claim 4, further comprising a second storage location to store an identifier of the other input/output device.

6. The apparatus of claim 5, wherein the identifier includes a bus number, a device number, and a function number.

7. The apparatus of claim 1, further comprising a second storage location to store an identifier of the input device.

8. The apparatus of claim 7, wherein the identifier includes a bus number, a device number, and a function number.

9. A method comprising:

receiving a first configuration transaction directed to an input/output device;

determining that the input/output device is unavailable; and

redirecting the first configuration transaction to an other target.

10. The method of claim 9, further comprising responding, by the other target, to the first configuration transaction.

11. The method of claim 9, the method further comprising storing in a storage location an identifier of the input/output device prior to powering down the input/output device, wherein determining that the input/output device is unavailable includes comparing an identifier of the target received in the first configuration transaction with the contents of the storage location.

12. The method of claim 9, further comprising powering down the input/output device prior to receiving the first configuration transaction.

13. The method of claim 12, further comprising initiating the first configuration transaction response prior to receiving the first configuration transaction, wherein initiating the first configuration transaction is performed as part of a re-scan operation to support a plug-and-play feature.

14. The method of claim 13, further comprising:

powering up the input/output device after redirecting the first configuration transaction;

receiving a second configuration transaction directed to the input/output device after powering up the input/output device; and

responding, by the input/output device, to the second configuration transaction without reloading a driver for the input/output device.

15. The method of claim 9, wherein the other target is a memory location, the method further comprising finding a base address of the memory location in a programmable storage location.

16. The method of claim 9, wherein the other target is an other input/output device, the method further comprising finding a bus number, a device number, and a function number of the other input/output device in a programmable storage location.

17. A system comprising:

a first input/output device;

a processor to initiate a configuration transaction directed to the first input/output device;

a first storage location to store an indication that the input/output device is inaccessible;

a decoder to decode the configuration transaction and redirect the configuration transaction to an other target if the contents of the first storage location indicate that the input/output device is inaccessible

18. The system of claim 17, further comprising a memory, wherein the other target is a region in the memory.

19. The system of claim 17, further comprising a second input/output device, wherein the other target is the second input/output device.

20. The system of claim 17, wherein the decoder is also to convert the configuration transaction to a Peripheral Component Interconnect memory transaction.