Messages in this thread |  | | | Date | Thu, 08 Jun 2006 21:25:02 -0400 (EDT) | | From | Nicolas Pitre <> | | Subject | Re: [linux-usb-devel] [PATCH] limit power budget on spitz |
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On Thu, 8 Jun 2006, David Brownell wrote:
> On Thursday 08 June 2006 2:49 pm, Richard Purdie wrote: > > > > > One additional nuance: if > > > the kernel doesn't have that driver configured, that's another reason not > > > to bother registering its device. > > > > This is where you start to add ugly ifdefs and generally start making > > the code look horrible. The device model separated the drivers and the > > devices to deal with this issue as I see it. > > Enumeration is a separate issue. You wouldn't argue that every potential > PCI or USB device must get registered, right? Only the ones that are > actually _present_ get registered.
You are both saying the same thing so far.
> But here you argue that platform bus should not work that same way ... it > should register devices that can't be present. If nothing else, that's > an inconsistent aproach.
That's not what Richard is saying.
He replied to your assertion where you said: "if the kernel doesn't have that driver configured, that's another reason not to bother registering its device" to which he disagreed, and I disagree too.
> Plus, consider the common situation that a given pin could potentially > be used with several different devices. On a given board, only one of > those devices will be wired up. It's counterproductive to register any > of the others ... error prone, waste-of-kernel-address-space, etc.
No one disagreed with that AFAICS.
> > Generally I'd say its > > cleaner just to let the device register, then if a module comes along at > > some later point, the device is there for it. > > Whether the device is there or not is a hardware issue. Board schematics > will show which devices are relevant ... registering any others is just > wastage.
But you originally talked about _driver_ configuration dictating if a _device_ should be registered or not.
The _device_ should indeed be registered based on _hardware_ config, not _driver_ config.
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