1. In a system that includes a bus used for communication between a host computer and one or more devices, and a protocol analyzer that is configured to monitor traffic on the bus, a method for the protocol analyzer triggering an action related to capture of data on the bus when a protocol of the bus is functioning properly, the method comprising the protocol analyzer performing the following:
monitoring traffic on the bus;
detecting a trace packet on the bus, wherein the trace packet is generated by a host computer in response to a condition with a device, and wherein the trace packet is sent over the bus to an invalid address; and
in response to detecting the trace packet sent to the invalid address, triggering an action related to capture of data on the bus.
2. A method as recited in claim 1, wherein the trace packet was sent on the bus even though no error was detected with the device.
3. A method as defined in claim 1, wherein the condition includes the detection of an error with the device during enumeration of the device.
4. A method as defined in claim 3, wherein detection of the error includes a host failing to receive a response from the device.
5. A method as defined in claim 1, wherein the trace packet is synchronously sent on the bus to the invalid address such that the protocol analyzer is externally triggered without requiring an external interface to the device.
6. A method as defined in claim 1, wherein the trace packet is periodically sent on the bus to the invalid address even when an error is not detected.
7. A method as defined in claim 1, wherein the bus is a Universal Serial Bus.
8. A method as defined in claim 1, wherein the bus is an IEEE 1394 bus.
9. A method as defined in claim 1, wherein the trace packet is generated by a low level device driver.
10. A method as defined in claim 1, wherein the invalid address is a root hub address.
11. A method as defined in claim 1, wherein the condition with the device includes the detection of a state with the device.
12. A method as defined in claim 1, wherein the condition with the device includes the detection of a protocol transition.
13. A method as defined in claim 1, wherein the triggered action includes:
causing the protocol analyzer to begin capturing data on the bus.
14. A method as defined in claim 1, wherein the triggered action includes:
causing the protocol analyzer to stop capturing data on the bus such that recent events prior to the trace packet are stored in a cache of the protocol analyzer.
15. A computer program product for use in a system that includes a bus used for communication between a host computer and one or more devices, and a protocol analyzer that is configured to monitor traffic on the bus, the computer program product comprising one or more computer-readable storage media having computer-executable instructions for implementing a method for the protocol analyzer triggering an action related to capture of data on the bus when a protocol of the bus is functioning properly, wherein the method comprises the protocol analyzer performing the following:
monitoring traffic on the bus;
detecting a trace packet on the bus, wherein the trace packet is generated by a host computer in response to a condition with a device, and wherein the trace packet is sent over the bus to an invalid address; and
in response to detecting the trace packet sent to the invalid address, triggering an action related to capture of data on the bus.
16. A computer program product as recited in claim 15, wherein the trace packet was sent on the bus even though no error was detected with the device.
17. A computer program product as defined in claim 15, wherein the invalid address is a root hub address.
18. A computer program product as defined in claim 15, wherein the triggered action includes:
causing the protocol analyzer to begin capturing data on the bus.
19. A computer program product as defined in claim 15, wherein the triggered action includes:
causing the protocol analyzer to stop capturing data on the bus such that recent events prior to the trace packet are stored in a cache of the protocol analyzer.
20. A protocol analyzer configured to monitor traffic on a bus which is used in a system for communication between a host computer and one or more devices, wherein the and a protocol analyzer implements a method for triggering an action related to capture of data on the bus when a protocol of the bus is functioning properly, and wherein the protocol analyzer comprises:
means for monitoring traffic on the bus;
means for detecting a trace packet on the bus, wherein the trace packet is generated by a host computer in response to a condition with a device, and wherein the trace packet is sent over the bus to an invalid address; and
means for triggering an action related to capture of data on the bus in response to detecting the trace packet sent to the invalid address.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. (canceled)
2. A vehicular braking apparatus comprising:
a shut-off valve that shuts off, as needed, a flow of a working liquid from a wheel cylinder to a master cylinder;
a pressure increase-decrease control valve that increases and decreases a pressure in the wheel cylinder;
a reservoir that receives and stores in a reservoir chamber the working liquid from the wheel cylinder when the pressure increase-decrease control valve is in a pressure decrease position and at a time when the working liquid in the master cylinder is pressurized;
pressurizing supply means for sucking in and pressurizing the working liquid from the reservoir chamber and supplying the working liquid to the wheel cylinder via the pressure increase-decrease control valve when the pressure increase-decrease control valve is in a pressure increase position; and
a communication control valve that controls communication between the master cylinder and the reservoir chamber;
wherein,
the communication control valve includes a normally-closed on-off valve, and valve-opening means for opening the on-off valve by being driven by means of the suction pressure of the pressurizing supply means;
the normally-closed on-off valve comprises a valve element and a valve element-urging member for urging the valve element to a close position, and the communication control valve maintains a closed condition at the time of nonbraking;
the valve-opening means includes a reciprocally movable member disposed within the reservoir so as to be reciprocally movable in a direction of opening and closing of the on-off valve and that is driven in a direction of opening of the on-off valve by means of the suction pressure of the pressurizing supply means;
the direction of opening of the on-off valve is a direction of reduction of a volume of the reservoir chamber; and
the on-off valve is a spool valve that opens and closes through reciprocal displacement of a spool, which serves as the valve element, in relation to a valve housing.
3. A vehicular braking apparatus according to claim 2, wherein, until the suction pressure of the pressurizing supply means attains a predetermined value or greater, the working liquid can flow from the reservoir to the pressurizing supply means in a state in which the communication control valve maintains a closed condition.
4. A vehicular braking apparatus according to claim 2, wherein, when an amount of movement of the reciprocally movable member in the direction of opening of the on-off valve from a position at the time of nonbraking is equal to or less than a preset amount of idle movement, the valve-opening means does not open the on-off valve.
5. A vehicular braking apparatus according to claim 2, wherein the reservoir has a housing, a reservoir piston disposed within the housing in a reciprocally movable manner and that defines the reservoir chamber in cooperation with the housing, and piston-urging means for urging the reservoir piston in the direction of reduction of the volume of the reservoir chamber, and the reservoir chamber communicates at all times with a suction side of the pressurizing supply means and communicates with the master cylinder via the communication control valve.
6. A vehicular braking apparatus according to claim 2, wherein the valve element, in cooperation with the valve housing, defines a variable-volume chamber whose volume increases and decreases according to a reciprocal movement of the valve element so as to allow the reciprocal movement of the valve element, and includes an internal passage for establishing communication at all times between the variable-volume chamber and the reservoir chamber.
7. A vehicular braking apparatus according to claim 2, wherein the spool is united with the reciprocally movable member.
8. A reservoir provided in a vehicular braking apparatus comprising:
a shut-off valve for shutting off, as needed, a flow of a working liquid from a wheel cylinder to a master cylinder;
a pressure increase-decrease control valve that increases and decreases a pressure in the wheel cylinder;
pressurizing supply means for pressurizing the working liquid and supplying the working liquid to the wheel cylinder via the pressure increase-decrease control valve at a time when the pressure increase-decrease control valve is in a pressure increase position and the working liquid in the master cylinder is pressurized, the reservoir receiving and storing in a reservoir chamber the working liquid from the wheel cylinder when the pressure increase-decrease control valve is in a pressure decrease position, the reservoir chamber communicating with a suction side of the pressurizing supply means; and
a communication control valve that controls communication between the master cylinder and the reservoir chamber;
wherein,
the communication control valve includes a normally-closed on-off valve, and valve-opening means for opening the on-off valve by being driven by means of the suction pressure of the pressurizing supply means;
the normally-closed on-off valve comprises a valve element and a valve element-urging member for urging the valve element to a close position, and the communication control valve maintains a closed condition at the time of nonbraking;
the valve-opening means includes a reciprocally movable member disposed within the reservoir so as to be reciprocally movable in a direction of opening and closing of the on-off valve and that is driven in a direction of opening of the on-off valve by means of the suction pressure of the pressurizing supply means;
the direction of opening of the on-off valve is a direction of reduction of a volume of the reservoir chamber; and the on-off valve is a spool valve that opens and closes through reciprocal displacement of a spool, which serves as the valve element, in relation to a valve housing.