PCI SIO devices hog interrupts, cause lock order problems

[M. Warner Losh]

In message: <012301c48e25$14924180$84cba8c0 at hh.kew.com>
            "Andrew H. Derbyshire" <ahd at kew.com> writes:
: Basically, any PCI SIO device hogs its interrupt if the PUC device is not
: also in the kernel, and this causes real problems for any environment like
: mine where pulling the modem is not trivial.  Does the distributed GENERIC
: kernel have room for the PUC device?  Are there side effects that PUC should
: be excluded from GENERIC?

puc should be in GENERIC, imho.

: As a bonus, there appears to be a bug with kernel locking exposed by the
: problem.  With the stock generic kernel, the XL device reports it couldn't
: map the interrupt, and then a lock order reversal is reported.  (See the
: attached log for the gory details).

This is a known problem.

Warner