Alex Williamson wrote: > On Mon, 2009-11-30 at 13:52 -0800, Yinghai Lu wrote: >> Alex Williamson wrote: >>> On Mon, 2009-11-30 at 13:36 -0800, Yinghai Lu wrote: >>>> Alex Williamson wrote: >>>>> - if (pref_mem64) { >>>>> - /* Set the upper 32 bits of PREF base & limit. */ >>>>> - pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, bu); >>>>> - pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, lu); >>>>> - } >>>>> + /* Set the upper 32 bits of PREF base & limit. */ >>>>> + pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, bu); >>>>> + pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, lu); >>>>> >>>>> pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, bus->bridge_ctl); >>>>> } >>>> when pref_mem64=0 it means that pref register is only 32 bit, we should not touch upper 32bits. >>> Did you read my patch description? In that case bu = lu = 0 and we >>> clear whatever state the BIOS left for those registers. >> if HW state that reg is only 32bit pref, why should we care about the upper 32bit? > > In my case, we're programming a 32bit prefetchable range into a 64bit > capable bridge. We can't just assume the upper 32bits are already zero. > >> looks like that your bridge device need quirk to clear that so called upper 32bit for it. > > I don't believe the PCI spec dictates whether the upper 32bit base > should be 0 or -1, so it's purely a BIOS initialization choice and Linux > should properly handle both. If the hardware only supports 32bit > prefetchable windows, the hardware will drop the write, just as it did > for every 2.6 kernel before 1f82de10. Thanks, current code: #define PCI_PREF_RANGE_TYPE_MASK 0x0fUL #define PCI_PREF_RANGE_TYPE_32 0x00 #define PCI_PREF_RANGE_TYPE_64 0x01 #define PCI_PREF_RANGE_MASK (~0x0fUL) if the HW state the pref mmio is 64bit, we will touch upper 32bit. otherwise we will not touch it. please post your boot log to show the problem. YH -- 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