Date: Wed, 11 Dec 2013 16:26:11 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: Justin Hibbits <jhibbits@freebsd.org>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: Request for testing an alternate branch Message-ID: <201312111626.12035.jhb@freebsd.org> In-Reply-To: <20131204222113.39fb23dd@zhabar.gateway.2wire.net> References: <20131204222113.39fb23dd@zhabar.gateway.2wire.net>
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On Thursday, December 05, 2013 1:21:13 am Justin Hibbits wrote: > I've been working on the projects/pmac_pmu branch for some time now to > add suspend/resume as well as CPU speed change for certain PowerPC > machines, about a year since I created the branch, and now it's stable > enough that I want to merge it into HEAD, hence this request. However, > it does touch several drivers, turning them into "early drivers", such > that they can be initialized, and suspended and resumed at a different > time. Saying that, I do need testing from other architectures, to make > sure I haven't broken anything. > > The technical details: > > To get proper ordering, I've extended the bus_generic_suspend() and > bus_generic_resume() to do multiple passes. Devices which cannot be > enabled or disabled at the current pass level would return an EAGAIN. > This could possibly cause problems, since it's an addition to an > existing API rather than a new API to run along side it, so it needs a > great deal of testing. It works fine on PowerPC, but I don't have any > i386/amd64 or sparc64 hardware to test it on, so would like others who > do to test it. I don't think that it would impact x86 at all (testing > is obviously required), because the nexus is not an EARLY_DRIVER_MODULE, > so all devices would be handled at the same pass. But, I do know the > sparc64 has an EARLY_DRIVER_MODULE() nexus, so that will likely be > impacted. I have patches to change many x86 drivers to use EARLY_DRIVER_MODULE() FWIW. Also, I'm still not a fan of the EAGAIN approach. I'd rather have a method in bus_if.m to suspend or resume a single device and to track that a device is suspended or resumed via a device_t flag or some such. (I think I had suggested this previously as it would also allow us to have a tool to suspend/resume individual drivers at runtime apart from a full suspend/resume request). -- John Baldwin
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