TRINATH KARRI
Member
Does PCI specification has RC to EP MSI support
Does PCI specification has RC to EP MSI support
- Thread starter TRINATH KARRI
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Yeah dude, the PCI specification does include support for Root Complex (RC) to Endpoint (EP) Message Signaled Interrupts (MSI). It's a feature that allows devices on the PCI bus to efficiently communicate interrupt requests, reducing overhead and improving system performance. This feature is commonly used in modern systems to enhance interrupt handling and optimize device communication. So, rest assured, MSI support is part of the PCI spec!
OP
TRINATH KARRI
Member
please read my question carefully. i am asking for "RC to EP" not "EP to RC"
Oops, my bad! I apologize for the misunderstanding, dude. The PCI specification does not include direct support for RC to EP MSI. The MSI mechanism is primarily designed for an Endpoint (EP) to send interrupts to the Root Complex (RC) or other devices. So, if you're trying to communicate from RC to EP using MSI, you might need to explore alternative methods. Let me know if there's anything else I can help you with!
OP
TRINATH KARRI
Member
What are those alternate methods ?
Ah, my apologies for not mentioning the alternative methods earlier, dude. If you want to communicate from the Root Complex (RC) to an Endpoint (EP) while bypassing the MSI mechanism, you can consider a couple of options:
1. Legacy PCI Interrupts: The PCI specification supports legacy interrupts, which allow the RC to send interrupts directly to the EP using shared interrupt lines.
2. Message Signaled Interrupts Extended (MSI-X): This is an extension to MSI that enables the EP to allocate and manage multiple interrupt vectors. While primarily designed for EP to RC communication, with proper implementation, it can be used for RC to EP communication as well.
Both of these methods have their own considerations and might require additional configuration and programming. So, make sure to refer to the device documentation and specifications to determine the best approach for your specific setup. Let me know if you have any more questions, dude!
OP
TRINATH KARRI
Member
can i use leagacy pci interrupts for RC to EP interrupt generation ? i dont think so
You're absolutely right, dude. My bad for the confusion in my previous response. The legacy PCI interrupts are primarily designed for the Endpoint (EP) devices to generate interrupts and not meant for the Root Complex (RC) to initiate interrupt requests to the EP. So, my apologies for the incorrect information.
For RC to EP interrupt generation, the Message Signaled Interrupt (MSI) mechanism is commonly used. This allows the EP to allocate and manage interrupt vectors and enables efficient communication between the RC and EP.
I appreciate you pointing out the mistake, and I apologize for any confusion caused. Let me know if you have any further questions or need any more help!
OP
TRINATH KARRI
Member
For RC to EP interrupt generation, the Message Signaled Interrupt (MSI) mechanism is commonly used. Incorrect
My apologies once again, dude. I provided incorrect information in my previous response. You are right, the Message Signaled Interrupt (MSI) mechanism is primarily designed for the Endpoint (EP) devices to generate interrupts, not for the Root Complex (RC) to initiate interrupt requests to the EP.
If the RC needs to generate interrupts and communicate with the EP, it typically does so through other means like memory-mapped I/O (MMIO) or specific control registers provided by the EP. The exact method of communication will depend on the specific device or system you're working with.
I apologize for any confusion caused, and I appreciate your understanding. If you have any more questions or need further assistance, feel free to ask!
