On Mon, Nov 08, 2010 at 04:35:38PM +1300, Alexey Korolev wrote: > > - >4GB 64bit bar allocation > > Your patche tries to address this issue. But it breaks PCI-to-PCI > > bridge filtering support. > Hmm, it is quite possible, as we don't know a lot about seabios PCI-to-PCI > bridge filtering support. > Just out of curiosity: what is the issue?
It's pci_bios_init_device_bridge() in pciinit.c. The function touches pci_bios_io_addr, pci_bios_mem_addr, and pci_bios_prefmem_addr. So we need to modify, not only pci_bios_allocate_region(), but also pci_bios_init_device_bridge(). The function programs the P2P bridge to forward IO/memory access on primary pci bus to secondary pci bus. It needs to be aware of 64bit BAR allocation. > > If the BAR size is huge (or there are too many BARs), the bar can't > > be allocated under 4G. So several persons want seabios to allocate > > such BARs at >4GB area complaining that OS can't use BARs that seabios > > didn't assigned. > > > > Others think such BAR can be left unallocated. > > Seabios role is to setup minimal basic environment for bootloader > > to boot OS, 64bit bar allocation is beyond it's role. > > bootloader/rombios usually doesn't handle BARs that is allocated > > beyond 4GB, and Modern OSes can re-arrange PCI bar allocation itself. > > So 64bit bar allocation support wouldn't be needed. > > > > I'm not sure if there is enough demand to support 64bit BAR allocation > > and if Kevin will accept it or not. Consensus is needed. > > What OS are you using? > > > For us >4GB allocation is welcome but not critical, because we mainly > use Linux versions 2.6.18 and newer. We've tested the seabios without > assignment of the regions which do not fit in first 32bit and it appears > to work fine. So for us 64bit bar allocation support wouldn't be needed. > > It is possible that people will use an ancient version of Linux, but the > probability of this event is very low. My position is same to yours. Welcome, but not critical. So the issue is, who will finish it. -- yamahata
