Date: Fri, 28 Feb 2003 17:02:01 -0500 From: Don Bowman <don@sandvine.com> To: "'freebsd-current@freebsd.org'" <freebsd-current@freebsd.org> Subject: problem with if_em and polling with RXSEQ interrupt? (and patch) Message-ID: <FE045D4D9F7AED4CBFF1B3B813C8533701B35BDE@mail.sandvine.com>
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In the if_em driver, it appears there is a possibility of
a system crash when POLLING is enabled in conjunction with
a link change.
em_disable_intr leaves the RXSEQ interrupt enabled (which
occurs when a link goes up or down). THe em_intr routine,
when in polling mode, just returns (with the interrupt
still active), which then re-enters it. the kern_poll
will never get a chance to do its POLL_AND_CHECK_STATUS in
this case.
I'm proposing to add to em_intr a call to em_poll with
POLL_AND_CHECK_STATUS if there is an interrupt pending
and we are in polling mode:
1086c1086,1087
< if (ifp->if_ipending & IFF_POLLING)
---
> if (ifp->if_ipending & IFF_POLLING) {
> em_poll(ifp, POLL_AND_CHECK_STATUS, 1);
1087a1089
> }
I also propose to enable the link status change interrupt in
em_disable_intr():
2259c2261
< (0xffffffff & ~E1000_IMC_RXSEQ));
---
> (0xffffffff & ~(E1000_IMC_RXSEQ | E1000_ICR_LSC)));
Does anybody have any comments on this?
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