CVS commit: src/sys/arch/x86

["Matthias Drochner" <drochner%netbsd.org@localhost>]

Module Name:    src
Committed By:   drochner
Date:           Mon Aug  1 11:08:03 UTC 2011

Modified Files:
        src/sys/arch/x86/include: pci_machdep_common.h
        src/sys/arch/x86/pci: pci_intr_machdep.c

Log Message:
add an experimental implementation of PCI MSIs (Message Signaled
Interrupts). Successfully tested with hdaudio and "wpi" wireless
ethernet.
notes:
-There seem to be buggy chips around which announce MSI support
 but don't correctly implement it. Thus the final word whether MSIs
 can be used should be by the driver.
-Only a single vector is supported. For multiple vectors, the IDT
 allocation code would have to be changed. (And we would possibly
 run into problems due to the limited number of vectors supported
 by the current code.)
-The code is "#if NIOAPIC > 0" because it uses the ioapic_edge
 interrupt stubs. These actually don't touch any ioapic, so this
 is somewhat a misnomer.
-MSIs can't be identified by a "pin" but only by a cpu/vector
 pair. Common intr code soesn't deal well with this yet.
-Drivers need to take care of saving/restoring MSI data in the device's
 config space on suspend/resume.


To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/sys/arch/x86/include/pci_machdep_common.h
cvs rdiff -u -r1.19 -r1.20 src/sys/arch/x86/pci/pci_intr_machdep.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.