From: pacman@kosh•dhis.org
To: segher@kernel•crashing.org (Segher Boessenkool)
Cc: linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org
Subject: Re: Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug,
Date: Thu, 28 Oct 2010 16:07:53 -0500 (GMT+5) [thread overview]
Message-ID: <20101028210753.22240.qmail@kosh.dhis.org> (raw)
In-Reply-To: <52441.84.105.60.153.1288295412.squirrel@gate.crashing.org>
Segher Boessenkool writes:
>
> > So is it wrong to leave the host controller enabled when the OS is booted?
>
> Yes. Or, rather, there should be some way for the client to turn off
> all dma and interrupt activity; if the client closes the ihandles in
> "/chosen", and perhaps calls "quiesce", that should be enough.
Sounds good to me, I only wish someone had written down what "quiesce" means.
> >
> > Almost all of my devices are under that PCI node. What will I prove by
> > disabling them?
>
> You should put it after "load", and before "go".
>
> It should give you a working system; it's a sledgehammer workaround.
I can do it a little more gracefully than that. This works to deactivate the
problem devices manually:
1 lbflip 80000000 8 + rl!
1 lbflip 80001000 8 + rl!
where 80000000 and 80001000 have been obtained from
/pci@80000000/usb@5/assigned-addresses and
/pci@80000000/usb@5,1/assigned-addresses; 8 is the offset of the
HcCommandStatus register; and the 1 bit is HostControllerReset (HCR).
Now I'm just trying to find the more correct way of doing it, without
hardcoded addresses. That'll be something like this:
search the device tree for OHCI nodes
for each OHCI node
get assigned-addresses
map-in
set HCR
wait for acknowledgement
map-out
which can be done any time before the quiesce call, since that marks the
point where the kernel assumes that there are no devices writing to memory.
Sound good?
--
Alan Curry
next prev parent reply other threads:[~2010-10-28 21:07 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20101009095718.1775.qmail@kosh.dhis.org>
[not found] ` <20101011143022.GD30667@csn.ul.ie>
2010-10-11 21:00 ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 Andrew Morton
2010-10-13 14:40 ` Mel Gorman
2010-10-13 17:52 ` pacman
2010-10-18 11:33 ` Mel Gorman
2010-10-18 19:10 ` pacman
2010-10-18 21:10 ` Benjamin Herrenschmidt
2010-10-18 21:33 ` pacman
2010-10-19 10:16 ` Benjamin Herrenschmidt
2010-10-19 18:10 ` pacman
2010-10-19 20:47 ` Segher Boessenkool
2010-10-19 21:02 ` Benjamin Herrenschmidt
2010-10-20 3:23 ` pacman
2010-10-20 10:32 ` Benjamin Herrenschmidt
2010-10-20 18:33 ` pacman
2010-10-20 20:56 ` Benjamin Herrenschmidt
2010-10-22 9:15 ` pacman
2010-10-27 8:57 ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) pacman
2010-10-27 10:13 ` Olaf Hering
2010-10-27 21:04 ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, pacman
2010-10-27 22:05 ` Segher Boessenkool
2010-10-27 22:58 ` pacman
2010-10-27 23:33 ` Segher Boessenkool
2010-10-28 1:11 ` pacman
2010-10-28 19:50 ` Segher Boessenkool
2010-10-28 21:07 ` pacman [this message]
2010-10-29 0:16 ` Segher Boessenkool
2010-11-05 6:43 ` pacman
2010-11-29 5:44 ` Benjamin Herrenschmidt
2010-10-27 13:27 ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) Benjamin Herrenschmidt
2010-10-19 20:58 ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 Benjamin Herrenschmidt
2010-10-18 19:37 ` Andrew Morton
2010-10-18 21:02 ` Benjamin Herrenschmidt
2010-10-18 21:55 ` Thomas Gleixner
2010-10-19 16:24 ` Helmut Grohne
2010-10-19 16:42 ` Thomas Gleixner
2010-10-18 20:59 ` Benjamin Herrenschmidt
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