svn commit: r189367 - head/sys/dev/pci

[M. Warner Losh]

In message: <1236224629.1384.22.camel at widget.2hip.net>
            Robert Noland <rnoland at FreeBSD.org> writes:
: On Wed, 2009-03-04 at 19:41 -0700, M. Warner Losh wrote:
: > In message: <1236218572.1384.19.camel at widget.2hip.net>
: >             Robert Noland <rnoland at FreeBSD.org> writes:
: > : On Wed, 2009-03-04 at 13:56 -0700, M. Warner Losh wrote:
: > : > In message: <200903041823.n24INmcc049524 at svn.freebsd.org>
: > : >             Robert Noland <rnoland at freebsd.org> writes:
: > : > : Author: rnoland
: > : > : Date: Wed Mar  4 18:23:48 2009
: > : > : New Revision: 189367
: > : > : URL: http://svn.freebsd.org/changeset/base/189367
: > : > : 
: > : > : Log:
: > : > :   Extend the management of PCIM_CMD_INTxDIS.
: > : > :   
: > : > :   We now explicitly enable INTx during bus_setup_intr() if it is needed.
: > : > :   Several of the ata drivers were managing this bit internally.  This is
: > : > :   better handled in pci and it should work for all drivers now.
: > : > :   
: > : > :   We also mask INTx during bus_teardown_intr() by setting this bit.
: > : > :   
: > : > :   Reviewed by:	jhb
: > : > :   MFC after:	3 days
: > : > 
: > : > Note: the INTxDIS bit is new in PCI 3.0, and has no effect on earlier
: > : > devices.  This should be highlighted in the comments somewhere...
: > : 
: > : It is documented in 2.3 as well, I'm not sure about previous versions of
: > : the spec though.
: > 
: > It isn't in 2.2, and even after 2.3 it is "optional".
: 
: The bit should be unused if it isn't supported by a given piece of
: hardware.  If it doesn't do anything, we are no worse off than before.
: I don't think this will cause any harm, only goodness when it is
: supported.

Yes.  I agree.  This is just the sort of bit, however, that people
looking for an interrupt storm would latch on to as being just the
ticket...  Which is why I suggested a comment...

Warner