4 ms·

> was written as a singleton Can you please explain this? What does it mean exactly? And is it different in versions of the kernel that aren’t the ones you exp

• ouzu 6y ago
  A singleton is a design pattern making sure only one instance of an object can exist
  • qubex 6y ago
    I know the term but I can’t quite understand how to interpret it in this specific context. Does it mean you can only program an FPGA once? Only one FPGA? One object per bus? I really don’t understand it.
    • anewvillager 6y ago
      > you can't configure additional peripheral FPGAs. My understanding is that you can only have a single FPGA.
• elevation 6y ago
  The FPGA Manager in K4.9 and K4.14 worked fine to fully manage a single FPGA through multiple configuration cycles through both the sysfs and the configfs interfaces. On a system with multiple FPGAs, FPGA Manager would fully manage any one of them, as long as it was the first device it probed. The second probe would partially fail after creating nodes on sysfs, and a third probe would crash the kernel. For that particular system, the upstream vendor hasn't rolled out K4.19 support yet. My initial impression of the FPGA Manager code in 4.19 is that this may be fixed (that an FPGA Manager looks to be allocated per driver instead of one global singleton) but I haven't backported it for testing yet. I think the interfaces FPGA Manager are well designed, its seems to be adequately expressive for even exotic uses, but I would love to see the implementation mature a bit.