Date: Fri, 03 Oct 2003 16:51:14 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: jhb@freebsd.org Cc: julian@elischer.org Subject: Re: PERFORCE change 38917 for review Message-ID: <20031003.165114.08027459.imp@bsdimp.com> In-Reply-To: <XFMail.20031003131759.jhb@FreeBSD.org> References: <20031003.000052.96921421.imp@bsdimp.com> <XFMail.20031003131759.jhb@FreeBSD.org>
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In message: <XFMail.20031003131759.jhb@FreeBSD.org>
John Baldwin <jhb@freebsd.org> writes:
:
: On 03-Oct-2003 M. Warner Losh wrote:
: > In message: <20031002022135.GA26666@perrin.nxad.com>
: > Hiten Pandya <hmp@nxad.com> writes:
: >: Does this also include PCI Hotplugging or is this going to be
: >: a separate effort?
: >
: > Yes and no.
: >
: > We already have removable devices in the tree. CardBus, PC Card, USB
: > and Firewire. Right now the drivers take liberties and chances and
: > there are a number of ugly races that rear their ugly heads. This is
: > an effort to clean that up and make things totally safe in all the
: > cases that we can think of, and to document those areas where we
: > can't.
: >
: > There's no specific plans on my part to implement the hot plug state
: > transition and deal with it. People have raised their hands in the
: > past to work on it, but so far no one has made significant progress in
: > public view.
:
: BTW, I thought of a locking concern in attach routines this morning.
: Basically, as soon as a driver does bus_setup_intr(), it needs to start
: using any locks shared with its interrupt handler and the hardware
: and driver state need to be able to handle having the handler invoked
: when that function is called. The reason is that the device may be
: attached to an interrupt line shared with another device and thus the
: other device may generate an interrupt and call the new devices handler
: before bus_setup_intr() even returns. Similarly, locking will be
: needed after calls to disk_create(), if_attach(), etc.
Yes. That's true. I'll keep it in mind.
Warner
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