Date: Sun, 29 Jan 2012 16:41:24 +0100 From: Marius Strobl <marius@alchemy.franken.de> To: John Baldwin <jhb@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r193833 - in head: share/man/man9 sys/kern sys/sys Message-ID: <20120129154124.GB18227@alchemy.franken.de> In-Reply-To: <200906091426.n59EQNRC074046@svn.freebsd.org> References: <200906091426.n59EQNRC074046@svn.freebsd.org>
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On Tue, Jun 09, 2009 at 02:26:23PM +0000, John Baldwin wrote: > Author: jhb > Date: Tue Jun 9 14:26:23 2009 > New Revision: 193833 > URL: http://svn.freebsd.org/changeset/base/193833 > > Log: > Add support for multiple passes of the device tree during the boot-time > probe. The current device order is unchanged. This commit just adds the > infrastructure and ABI changes so that it is easier to merge later changes > into 8.x. > - Driver attachments now have an associated pass level. Attachments are > not allowed to probe or attach to drivers until the system-wide pass level > is >= the attachment's pass level. By default driver attachments use the > "last" pass level (BUS_PASS_DEFAULT). Driver's that wish to probe during > an earlier pass use EARLY_DRIVER_MODULE() instead of DRIVER_MODULE() which > accepts the pass level as an additional parameter. > - A new method BUS_NEW_PASS has been added to the bus interface. This > method is invoked when the system-wide pass level is changed to kick off > a rescan of the device tree so that drivers that have just been made > "eligible" can probe and attach. > - The bus_generic_new_pass() function provides a default implementation of > BUS_NEW_PASS(). It first allows drivers that were just made eligible for > this pass to identify new child devices. Then it propogates the rescan to > child devices that already have an attached driver by invoking their > BUS_NEW_PASS() method. It also reprobes devices without a driver. > - BUS_PROBE_NOMATCH() is only invoked for devices that do not have > an attached driver after being scanned during the final pass. > - The bus_set_pass() function is used during boot to raise the pass level. > Currently it is only called once during root_bus_configure() to raise > the pass level to BUS_PASS_DEFAULT. This has the effect of probing all > devices in a single pass identical to previous behavior. > > Reviewed by: imp > Approved by: re (kib) > What would be necessary to finally enable support for multi-pass probing apart from the drivers also needing to set BUS_PASS_n if they want to take part earlier than BUS_PASS_DEFAULT)? My understanding is that this is should be as simple as changing root_bus_configure() to return BUS_PASS_ROOT instead of BUS_PASS_DEFAULT but the comment above that line actually talks about splitting the return value (?) up somehow ... Marius
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