[PATCH] Implement retry on linux sysfs pnp id file.

[Kay Sievers]

On Tue, 2008-09-23 at 00:51 -0700, Danny Kukawka wrote:
> On Montag, 22. September 2008, Drew Moseley wrote:
> > > Can you send the patch with diff -Nur or plain git diff?
> >
> > Updated patch below.
> >
> > > I'm currently not sure if we should do this. IMO the kernel should get
> > > fixed instead to provide the sysfs file only if the content/information
> > > is really available. Did you report the problem to the kernel guys?
> >
> > I've spoken w/ some kernel guys locally and they are of the opinion that
> > with sysfs, unfortunately, that's the way it has to be.  There is
> > precedence for this kind of sleep already in hald/linux/blockdev.c which
> > is what I modelled this patch after.
> 
> This is a really dirty hack. 
> 
> @Kay: Is this behavior normal? Is there a way to fix sysfs instead of sending 
> HAL into a loop?

Yep, "fix the kernel" is usually the right answer. There is almost
never a valid "the way it has to be" in sysfs. We fixed almost all know
issues so far, so this should be fixed too.

In:
  drivers/pnp/core.c
we have:
        ret = device_register(&dev->dev);
        if (ret)
                return ret;

        pnp_interface_attach_device(dev);

Which is broken, the attributes must not be created after the device
registration, they should be converted to "default bus attributes" and
all will work fine.

Kay