Messages in this thread | | | From | David Brownell <> | Subject | Re: Totally broken PCI PM calls | Date | Tue, 12 Oct 2004 11:52:53 -0700 |
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On Tuesday 12 October 2004 1:53 am, Pavel Machek wrote: > > If you are entering S4 or S5 at the end of swsusp basically should not > matter to anyone. What we tell the drivers is same in both cases.
The problem cases are on resume, where drivers can see different controller state. Both S4 and S5 resume can leave it in reset; fine. But from S4 the other option is the controller being in the state set up previously by the driver ... yet from S5 the other option is boot firmware (BIOS etc) mucking with it, leaving it in any of several states that are not otherwise documented for resume() paths.
Drivers that don't reset the controller in resume() will need special handling for those BIOS cases. That means USB HCDs, and maybe not a lot else yet in Linux.
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