Techniques of displaying host data on a monitor connected to a service processor during pre-boot initialization stage

1. A method of operating a service processor, comprising:

emulating a frame buffer;

determining whether the service processor is configured to generate display signals to be sent to a display based on images from the service processor or based on images from a host of the service processor;

when the service processor is configured to generate the display signals based on the images from the service processor:

generating a first image based on serial data received from the host through a serial port;

writing the first image to the emulated frame buffer; and

reading the first image from the emulated frame buffer and generating a first display signal to be sent to the display based on the first image;

when the service processor is configured to generate the display signals based on images from a host:

receiving and storing, at a physical buffer, a second image from the host; and

reading the second image from the physical frame buffer and generating a second display signal to be sent to the display based on the second image.

2. The method of claim 1 , wherein the emulating the frame buffer includes:

(a) allocating a dedicated area of a main memory of the service processor to function as a frame buffer,

(b) configuring a graphics processing unit of the service processor to write the images from the service processor to the dedicated area, and

(c) configuring a display controller of the service processor to read, from the dedicated area, the images from the service processor and to generate the display signals based on the images from the service processor;

wherein the first image is written to the dedicated area by the graphics processing unit, wherein the first display signal is generated by the display controller.

3. The method of claim 1 , further comprising:

receiving a power control command directed to the host;

determining whether the power control command is a power-on command or a power-off command;

when the power control command is the power-on command:

configuring the service processor to generate the display signals based on the images from the service processor; and

powering on the host.

4. The method of claim 3 , further comprising:

when the power control command is the power-off command:

configuring the service processor to generate the display signals based on the images from the host; and

powering off the host.

5. The method of claim 1 , further comprising:

when the service processor is configured to generate the display signals based on the images from the service processor, detecting that the serial data are received at the serial port, wherein the first image is generated in response to the detection.

6. The method of claim 1 , further comprising:

determining that the service processor is configured to redirect video of the host to a remote device;

reading the first image from the emulated frame buffer; and

redirecting the first image to the remote device.

7. The method of claim 1 , further comprising:

receiving an indication from the host; and

determining that the host has fully booted based on the indication; and

configuring the service processor to generate the display signals based on the images from the host.

8. The method of claim 7 , wherein the indication is a Power-On Self-Test (POST) code, a logic sensor state, or an Intelligent Platform Management Interface (IPMI) message.

9. An apparatus, the apparatus being a service processor, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

emulate a frame buffer;

determine whether the service processor is configured to generate display signals to be sent to a display based on images from the service processor or based on images from a host of the service processor;

when the service processor is configured to generate the display signals based on the images from the service processor:

generate a first image based on serial data received from the host through a serial port;

write the first image to the emulated frame buffer; and

read the first image from the emulated frame buffer and generate a first display signal to be sent to the display based on the first image;

when the service processor is configured to generate the display signals based on images from a host:

receive and store, at a physical buffer, a second image from the host; and

read the second image from the physical frame buffer and generate a second display signal to be sent to the display based on the second image.

10. The apparatus of claim 9 , wherein to emulate the frame buffer includes, the at least one processor is further configured to:

(a) allocate a dedicated area of a main memory of the service processor to function as a frame buffer,

(b) configure a graphics processing unit of the service processor to write the images from the service processor to the dedicated area, and

(c) configure a display controller of the service processor to read, from the dedicated area, the images from the service processor and to generate the display signals based on the images from the service processor;

wherein the first image is written to the dedicated area by the graphics processing unit, wherein the first display signal is generated by the display controller.

11. The apparatus of claim 9 , wherein the at least one processor is further configured to:

receive a power control command directed to the host;

determine whether the power control command is a power-on command or a power-off command;

when the power control command is the power-on command:

configure the service processor to generate the display signals based on the images from the service processor; and

power on the host.

12. The apparatus of claim 11 , wherein the at least one processor is further configured to:

when the power control command is the power-off command:

configure the service processor to generate the display signals based on the images from the host; and

power off the host.

13. The apparatus of claim 9 , wherein the at least one processor is further configured to:

when the service processor is configured to generate the display signals based on the images from the service processor, detect that the serial data are received at the serial port, wherein the first image is generated in response to the detection.

14. The apparatus of claim 9 , wherein the at least one processor is further configured to:

determine that the service processor is configured to redirect video of the host to a remote device;

read the first image from the emulated frame buffer; and

redirect the first image to the remote device.

15. The apparatus of claim 9 , wherein the at least one processor is further configured to:

receive an indication from the host; and

determine that the host has fully booted based on the indication; and

configure the service processor to generate the display signals based on the images from the host.

16. The apparatus of claim 15 , wherein the indication is a Power-On Self-Test (POST) code, a logic sensor state, or an Intelligent Platform Management Interface (IPMI) message.

17. A non-transitory computer-readable medium storing computer executable code for operating a service processor, comprising code to:

emulate a frame buffer;

determine whether the service processor is configured to generate display signals to be sent to a display based on images from the service processor or based on images from a host of the service processor;

when the service processor is configured to generate the display signals based on the images from the service processor:

generate a first image based on serial data received from the host through a serial port;

write the first image to the emulated frame buffer; and

read the first image from the emulated frame buffer and generate a first display signal to be sent to the display based on the first image;

when the service processor is configured to generate the display signals based on images from a host:

receive and store, at a physical buffer, a second image from the host; and

read the second image from the physical frame buffer and generate a second display signal to be sent to the display based on the second image.

18. The non-transitory computer-readable medium of claim 17 , wherein to emulate the frame buffer includes, the code is further configured to:

(a) allocate a dedicated area of a main memory of the service processor to function as a frame buffer,

(b) configure a graphics processing unit of the service processor to write the images from the service processor to the dedicated area, and

(c) configure a display controller of the service processor to read, from the dedicated area, the images from the service processor and to generate the display signals based on the images from the service processor;

wherein the first image is written to the dedicated area by the graphics processing unit, wherein the first display signal is generated by the display controller.

19. The non-transitory computer-readable medium of claim 17 , wherein the code is further configured to:

receive a power control command directed to the host;

determine whether the power control command is a power-on command or a power-off command;

when the power control command is the power-on command:

configure the service processor to generate the display signals based on the images from the service processor; and

power on the host.

20. The non-transitory computer-readable medium of claim 19 , wherein the code is further configured to:

when the power control command is the power-off command:

configure the service processor to generate the display signals based on the images from the host; and

power off the host.