Date: Mon, 1 Feb 2010 09:35:38 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-ia32@freebsd.org Cc: freebsd-ppc@freebsd.org, freebsd-arch@freebsd.org Subject: Re: About hot-plugging support in FreeBSD Message-ID: <201002010935.38861.jhb@freebsd.org> In-Reply-To: <8506939B503B404A84BBB12293FC45F60681AA1B@emailbng3.jnpr.net> References: <8506939B503B404A84BBB12293FC45F60681AA1B@emailbng3.jnpr.net>
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On Monday 01 February 2010 1:26:00 am Rajat Jain wrote: > Hi, > > I'm a newbie to the FreeBSD and have come from Linux background, hence > please pardon me if this is not the right list for my questions, and > please point me to the correct list: > > 1) Does FreeBSD support PCI-Express hot-plugging? I could not even find > any instances in the source code that suggest that even PCI hot-plugging > is supported. Is it supported? Can you please point me to appropriate > references in the code? No, not currently. > 2) How and WHERE in the code is the "PCI Enumeration" and the "PCI > resource allocation" done?: Enumeration is done in 'pci_add_children()' in sys/dev/pci/pci.c. Resource allocation is done in the same file in a few different places. > 2a) Does FreeBSD does its own PCI resource allocation / PCI bus > numbering, or does it simply use the one already done by the BIOS / > bootloader? It reuses the firmware allocations and can only handle simple cases to allocate resources for a BAR that the firmware did not initialize. > 2b) In case it does its own PCI resource management, is the PCI > Enumeration done only at the boot time, or devices can be detected and > added later at run-time as well? [Please note that for adding at run > time, we'll need certain PCI resource pre-reserved in anticipation of > any new devices] It shouldn't be too hard to support hot-plug. Note that the cardbus(4) code already does a form of PCI hot-plug, so some of the infrastructure for PCI hot-plug is already in place. -- John Baldwin
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