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The current isp116x driver is configured for level triggered (int_edge_triggered=0, default) and active high (int_act-high=1) interrupts. However, the setting for the corresponding GPIO interrupt is IORESOURCE_IRQ_HIGHEDGE. This might mean the interrupt is not being acknowledged correctly.
Planned Testing
- Figure out what might be causing the high PC104 interrupt load on some vipers. By swapping cards and looking at IRQ3 level on a scope, figure out whether the problem is associated with the Emerald serial cards or some of the Vipers.
- Try various USB interrupt configurations on Vipers and see if we can get the USB interrupt rate to drop, while sending data through a Bluetooth radio interfaced through the USB at data rates that were used at SCP. Could this be related to the issue of data corruption on USB flash drives that we see on Vipers, when two or more USB devices are connected?