On Wed, Aug 11, 2010 at 05:31:00PM -0700, Erik Gilling wrote:
> >> + if (!request_mem_region(r->start, (r->end - r->start) + 1,
> >> + dev_name(&pdev->dev))) {
> >> + ret = -EBUSY;
> >> + goto err0;
> >> + }
> >
> > I believe the platform bus does this for you already by calling
> > insert_resource() on all the platform bus ranges. See if /proc/iomem
> > is any different with or without this call to verify.
>
> You're right. Didn't realize this
There is a big difference between what the platform bus does and what
drivers do.
The platform bus adds the resources to the resource tree as they stand
without marking them _busy_. This means that they can be sub-divided
and other resources registered within their range.
request_mem_region() adds resources to the resource tree marking them
busy, detecting overlapping resources and indicating whether two
drivers are trying to claim the same resource region. In other words,
it's a preventative measure against two device drivers accessing the
same region.
You're absolutely right to do what you're doing above, please continue
to do so.
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