linux-kernel - Re: [PATCH 07/11] parisc: superio: do not use PCI resources before pci_enable

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Date:	Tue, 03 Aug 2010 11:38:48 -0500
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Vasiliy Kulikov <segooon@...il.com>
Cc:	kernel-janitors@...r.kernel.org, Kyle McMartin <kyle@...artin.ca>,
	Helge Deller <deller@....de>,
	"James E.J. Bottomley" <jejb@...isc-linux.org>,
	Frans Pop <elendil@...net.nl>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/11] parisc: superio: do not use PCI resources before
 pci_enable_device()

On Tue, 2010-08-03 at 20:35 +0400, Vasiliy Kulikov wrote:
> On Tue, Aug 03, 2010 at 11:11 -0500, James Bottomley wrote:
> > On Tue, 2010-08-03 at 19:44 +0400, Kulikov Vasiliy wrote:
> > >  drivers/parisc/superio.c |    5 +++--
> > >  1 files changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/parisc/superio.c b/drivers/parisc/superio.c
> > > index f7806d8..c8a36a2 100644
> > > --- a/drivers/parisc/superio.c
> > > +++ b/drivers/parisc/superio.c
> > > @@ -169,8 +169,6 @@ superio_init(struct pci_dev *pcidev)
> > >  	/* ...then properly fixup the USB to point at suckyio PIC */
> > >  	sio->usb_pdev->irq = superio_fixup_irq(sio->usb_pdev);
> > >  
> > > -	printk(KERN_INFO PFX "Found NS87560 Legacy I/O device at %s (IRQ %i)\n",
> > > -	       pci_name(pdev), pdev->irq);
> > >  
> > >  	pci_read_config_dword (pdev, SIO_SP1BAR, &sio->sp1_base);
> > >  	sio->sp1_base &= ~1;
> > > @@ -204,6 +202,9 @@ superio_init(struct pci_dev *pcidev)
> > >  	ret = pci_enable_device(pdev);
> > >  	BUG_ON(ret < 0);	/* not too much we can do about this... */
> > >  
> > > +	printk(KERN_INFO PFX "Found NS87560 Legacy I/O device at %s (IRQ %i)\n",
> > > +	       pci_name(pdev), pdev->irq);
> > > +
> > >  	/*
> > >  	 * Next project is programming the onboard interrupt controllers.
> > >  	 * PDC hasn't done this for us, since it's using polled I/O.
> > 
> > This really makes no sense; we want the information printed before we
> > start all the discovery prints, not after.
> 
> Right, I missed it.
> 
> > I assume lots of
> > initialisers want this too, so it looks particularly silly not to have
> > pci_name() returning the correct value until enable time.
> > 
> > If this is just the name initially assigned may change, this definitely
> > isn't true for parisc, and even for other things, it would be better to
> > print something than nothing.
> 
> Not name, but pdev-irq. I was not searching for pci_name() as you can
> see in coccinelle script :)
> 
> As it is only printing wrong value, the worst case is fooling user that
> reads logs.
> 
> 
> Is it OK to move pci_enable_device() just before this printk()?

Not really ... we need the device set up before it gets enabled.

If it's only the irq, then just leave it ... the name is more important
and an uninitialised IRQ returns -1 which is a reasonable signal of not
being set up yet ... but I think you'll find it will be pre setup on all
platforms.

However, 

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