[GitHub] [incubator-nuttx] xiaoxiang781216 edited a comment on pull request #1004: PCI Refactoring

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xiaoxiang781216 edited a comment on pull request #1004:
URL: https://github.com/apache/incubator-nuttx/pull/1004#issuecomment-634500532


   > There is an additional issue that we will likely need to resolve. Right now one one handler can be attached to a given IRQ. In reality multiple devices are frequently attached to the same interrupt line.
   > 
   > In Linux they handle this by instead of having single function defined in the IRQ struct, there is a linked list of handlers that is traversed.
   > https://www.oreilly.com/library/view/understanding-the-linux/0596005652/ch04s06.html#understandlk-CHP-4-TABLE-6
   > 
   > For now I am going to move forward with the requirement of a single device per IRQ, but this will likely have to be addressed at some point.
   
   The interrupt chain already support long time ago:
   ```
   commit d38be46655846948d3c7f6bb149fb757bf0498ea
   Author: zhuguangqing <zh...@pinecone.net>
   Date:   Fri Aug 24 15:10:23 2018 -0600
   
   sched/irq:  Add support interrupt chains in NuttX.
   
   IRQ chain is very useful in these cases:
   (1) Multiple hardware connect to the same request line(e.g. PCI),
   (2) Need multiple driver to support one hardware block (like Linux MFD)
   ```


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