Messages in this thread |  | | | Date | Tue, 15 May 2012 12:03:56 -0400 (EDT) | | From | Alan Stern <> | | Subject | Re: [RFC PATCH 1/3] block: add a flag to identify PM request |
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On Tue, 15 May 2012, Lin Ming wrote:
> On Tue, 2012-05-15 at 10:35 -0400, Alan Stern wrote: > > On Tue, 15 May 2012, Lin Ming wrote: > > > > > Add a flag REQ_PM to identify the request is PM related. > > > As an example, modify scsi code to use this flag. > > > > There already is such a flag; you don't need to add one. In fact, > > there already are _two_ such flags, and it would be best to remove one > > of them. In include/linux/blkdev.h: > > > > REQ_TYPE_PM_SUSPEND, /* suspend request */ > > REQ_TYPE_PM_RESUME, /* resume request */ > > > > Apparently they had been used by the old ide driver, but they don't > > seem to be used anywhere now. > > IDE code still uses both types and they are used for system > suspend/resume. See generic_ide_suspend and generic_ide_resume.
You're right, of course. I searched for "BLK_TYPE_PM_" instead of "REQ_TYPE_PM_". :-(
> But we need a flag to check whether it is runtime suspend/resume > request.
It should be possible to fix up the IDE code so that it uses the same flag for both suspend and resume. After all, there's no real danger of confusion -- you never get into a situation where you're not sure whether the current PM action is a suspend or a resume.
Alan Stern
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