On Mon, Jan 28, 2013 at 03:03:55PM -0700, Stephen Warren wrote: > On 01/28/2013 01:18 PM, Arnd Bergmann wrote: > > On Monday 28 January 2013, Thomas Petazzoni wrote: > >> From: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> > >> > >> [Thomas Petazzoni: > >> - Simplify capabilities handling. > >> - Move to a separate file. > >> - Fix mask used when writing a 4 bytes value.] > >> > >> Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> > >> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> > > > > Not even a description why this is needed? > > > > This patch (together with patch 8) seems like the most controversial > > one of the series, so you should better provide a really good reason > > why we would emulate something in software rather than using whatever > > hardware is there. > > At least on Tegra, there is no HW that exposes PCI configuration > registers for the host bridge itself. Only the root ports have exposed > PCI configuration registers. There was some debate re: whether a host > bridge device needed to exist or not. This patch makes such a device > exist if it's required. If Linux will discover properly (I strongly suspect it does) without the host bridge, then I would say to ditch this... The PCI-E standard requires a host bridge device, but if Linux doesn't require it then there is no reason to emulate one. That would simplify the question of PCI IDs - for Marvell's case and the sw root port bridge we can just copy the IDs from the bogus config space of the HW. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
