• Alex Williamson's avatar
    [SERIAL] 8250_hcdp needs irq sharing · 7c6d39f1
    Alex Williamson authored
    Patch from Alex Williamson
    
    Here's a trivial patch that makes 8250_hcdp setup the correct flags
    when IRQ sharing is enabled for serial ports.
    
    The HCDP table tells us if the device is a PCI UART.  We can use this
    to set the shared interrupt flag as well as program the interrupt with
    the correct polarity/trigger (should get rid of "changing vector <x>
    from IO-SAPIC-edge to IO-SAPIC-level" messages at bootup).  This also
    allows non-PCI UARTs to be left un-shareable, which is likely much
    more safe (edge triggered).
    
    The bit that I'm keying on is still part of the older 1.0a HCDP spec,
    so should be implemented (it was on all the boxes I tested).  If
    there's firmware out there that doesn't set this bit or the interrupt
    supported flag, the HCDP UART may run in polling mode, but should
    still be functional.
    7c6d39f1
8250_hcdp.h 1.48 KB