Date: Tue, 10 Jun 2003 14:16:32 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: marks@ripe.net Cc: orion@freebsd.org Subject: Re: Correct PCI suspend and resume operations Message-ID: <20030610.141632.71103986.imp@bsdimp.com> In-Reply-To: <20030610191504.GA8927@laptop.6bone.nl> References: <20030609035127.GA36909@laptop.6bone.nl> <200306101644.h5AGiawR066527@puma.icir.org> <20030610191504.GA8927@laptop.6bone.nl>
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In message: <20030610191504.GA8927@laptop.6bone.nl> Mark Santcroos <marks@ripe.net> writes: : On Tue, Jun 10, 2003 at 09:44:36AM -0700, Orion Hodson wrote: : > It looks like the pci configuration space state has been lost during : > the suspend and resume. This may be because the bus has removed power : > from the devices attached to it on suspend. : : For sure, in S4 mode the devices are powered down totally. : : > I've been through a cross section of drivers this morning and some : > explicitly save and restore the PCI configuration state space and : > others don't. The former seems like the safest path in most cases. : : Yes, it is absolutely necessary even. (For the reason stated above) : : > AFAICT, we don't common code for handling this and maybe there should : > be some rather than have each driver replicate this behaviour. : : In general, that would of course be better. However, I don't know if the : PCI layer (in this case) always knows enough. : On the other side, if the device itself has to do some special things, the : PCI layer could at least do the generic stuff. : (Warner, will this also be covered by the stuff you are doing?) Yes. I'm still working out those fields that we need to save. In general, BARs and a few other things aren't preserved accross D3 -> D0 state transitions. Some drivers try to cope, but it should be done in the main pci thread. Warner
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