Information processing apparatus including connection port to be connected to device, device connection method, and non-transitory computer-readable recording medium storing program for connecting device to information processing apparatus

1. An information processing apparatus comprising:

a processor configured to execute a program;

a memory configured to store the program;

a sideband bus;

a signal line;

connection ports configured to be attached to a device which receives, from the processor, a reset signal via the signal line, outputs, to the processor, a coupling state of whether the device is coupled to the connection port via the signal line and outputs, to the processor, bus-configuration information indicating a bus configuration of the device via the sideband bus; and

a state-information storage unit,

wherein the processor, based on the program, performs operations to:

acquire, from a storage unit included in the device, the bus-configuration information via the sideband bus when receiving the coupling state indicating that the device has been coupled to the connection port via the signal line; and

set a bus configuration of the connection port based on the bus-configuration information;

wherein the state-information storage unit is configured to store state information indicating a setting state of the bus configuration of the connection port,

wherein the processor compares the state information and the bus-configuration information and changes the bus configuration of the one or more connection ports based on a comparison result,

wherein the processor changes the bus configuration of the one or more connection ports by changing a value in a port setting register the connection port so that the bus configuration of the connection port matches the bus-configuration information when the state information and the bus-configuration information do not match each other; and

wherein the processor, after changing the bus configuration of the one or more connection ports, is configured to read the value port setting register whose value has been changed to verify the changing and supply the reset signal to the one or more connection ports individually.

2. The information processing apparatus according to claim 1 ,

wherein the processor is configured to reset the one or more connection ports.

3. The information processing apparatus according to claim 1 ,

wherein the processor is configured to acquire the bus-configuration information via the sideband bus from the storage unit.

4. A device connection method comprising:

acquiring, from a storage unit included in a device which receives, from a processor in an information processing apparatus, a reset signal via a signal line in the information processing apparatus, outputs, to the processor, a coupling state of whether the device is coupled to respective connection ports in the information processing apparatus via the signal line and outputs, to the processor, bus-configuration information indicating a bus configuration of the device via a sideband bus in the information processing apparatus, the bus-configuration information indicating a first bus configuration of the device via the sideband bus when receiving the coupling state indicating that the device has been coupled to the respective connection ports via the signal line;

acquiring, from a state-information storage unit in the information processing apparatus, state information indicating a second bus configuration of the respective connection ports to which the device is coupled;

comparing the first bus configuration and the second bus configuration by the processor;

changing the second bus configuration of the connection port based on a result of the comparing by changing a value in a port setting register;

changing the second bus configuration so as to match the first bus configuration when the first bus configuration and the second bus configuration do not match each other; and

reading, after changing the bus configuration of the respective connection ports, the value of the port setting register whose value has been changed to verify the changing and supply the reset signal to the respective connection ports individually.

5. The device connection method according to claim 4 , further comprising:

resetting the respective connection ports.

6. A non-transitory computer-readable recording medium storing a program for coupling a device, the program causing a computer to execute:

acquiring, from a storage unit included in a device which receives, from a processor in an information processing apparatus, a reset signal via a signal line in the information processing apparatus, outputs, to the processor, a coupling state of whether the device is coupled to respective connection ports in the information processing apparatus via the signal line and outputs, to the processor, bus-configuration information indicating a bus configuration of the device via a sideband bus in the information processing apparatus, the bus-configuration information via the sideband bus when receiving the coupling state indicating that the device has been coupled to the respective connection port via the signal line;

acquiring state information indicating a setting state of the bus configuration of the respective connection port from a state-information storage unit;

comparing the state information with the bus-configuration information; and

changing the bus configuration of the respective connection port based on the comparing by changing a value in a port setting register;

changing the bus configuration of the respective connection ports so as to match the bus-configuration information when the state information and the bus-configuration information do not match each other; and

reading, after changing the bus configuration of the respective connection ports, the value of the port setting register whose value has been changed to verify the changing and supply the reset signal to the respective connection ports individually.

7. The non-transitory computer-readable recording medium according to claim 6 , further comprising:

resetting the respective connection ports.