Date: Mon, 12 Mar 2012 16:57:47 +0100 From: Svatopluk Kraus <onwahe@gmail.com> To: hackers@freebsd.org Subject: pccbb device doesn't send device_shutdown() to childs (reboot freezes) Message-ID: <CAFHCsPVSwXps9K5-h_VjLKnQ56vHhPx%2BDs_isy8NAS7AnjdsTw@mail.gmail.com>
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Hi,
I solved very curious problem with rarely system (FreeBSD-9)
freezing during reboot. Finally, I found out that system freezes in ep
device callout. The part of device tree is following:
-> pccbb -> pccard -> ep
cbb_pci_shutdown() method in pccbb device places the cards in
reset, turns off the interrupts and powers down the socket. No child
has a chance to know about it. Thus, if ep device callout fires
between device_shutdown() is called on root device and interrupts are
disabled, the callout freezes in never-ending while loop, which reads
status from hardware (now without power).
I propose following change (editted by hand) in cbb_pci_shutdown():
struct cbb_softc *sc = (struct cbb_softc *)device_get_softc(brdev);
+
+ /* Inform all childs. */
+ bus_generic_shutdown(brdev);
+
/*
* We're about to pull the rug out from the card, so mark it as
* gone to prevent harm.
*/
sc->cardok = 0;
Futhermore, ep device (ed device too, ... ?) has not implemented
device_shutdown method. So, fixing pccbb device is not enough to solve
the freezing problem. I somehow patched the mentioned devices too, but
maybe someone more competent should do it for FreeBSD tree.
Svata
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