Re: ARM: ixp4xx regression (bisected) since v3.5-rc1

From: Brad Parker
Date: Sat Feb 23 2013 - 06:14:20 EST

On Sat, Feb 23, 2013 at 4:49 AM, Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxxx> wrote:
> On Sat, Feb 23, 2013 at 01:30:57AM -0500, Brad Parker wrote:
>> I then reversed this commit on 3.7.9 and the board booted
>> successfully. I'm not sure if this affects other boards of the same
>> arch or not, I only have access to a Pronghorn which also requires a
>> patch for the board files as they are not part of mainline.
> So it's an externally maintained board which breaks because of changes
> made in mainline? Likely, it's not been updated for the mainline changes
> correctly. *Sigh* unmerged external platform support sucks.
> What the commit you refer to above does is change the core code to do
> this:
> + if (hw->scan)
> + sys->bus = hw->scan(nr, sys);
> + else
> + sys->bus = pci_scan_root_bus(NULL, sys->busnr,
> + hw->ops, sys, &sys->resources);
> then changes each of the IXP4xx board files:
> + .ops = &ixp4xx_ops,
> - .scan = ixp4xx_scan_bus,
> and removes this:
> -struct pci_bus * __devinit ixp4xx_scan_bus(int nr, struct pci_sys_data *sys)
> -{
> - return pci_scan_root_bus(NULL, sys->busnr, &ixp4xx_ops, sys,
> - &sys->resources);
> -}
> What you will notice is that when .scan = NULL, and .ops = &ixp4xx_ops,
> the code is exactly identical.
> So, I doubt this is a regression with the mainline kernel, but is brought
> about by the non-visibility of your platforms code to mainline... I think
> your platform code needs updating appropriately.

You're right. I just forgot to add .ops, now it works without
reverting your commit. I think the patch could be merged in if someone
were willing to clean it up, I just don't really have the time. ADI
originally wrote the patch themselves for 2.6.26 and they claim that
it was included in 2.6.27 upstream, if that's true I assume it has
been removed at some point in the past. OpenWRT also maintains a
similar patch to get the board running on 3.3. I think the only thing
necessary to get it to 3.7/3.8 is remove .swizzle/.scan and add .ops.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at