> > Above 4GB, u need PAE + HIGHMEM option both enabled. Yes, u can > always use kmap() and friends API to map from > 4GB area to lowmem. > Then writing will just write to these lowmem area. > > Reference: > > http://www.ussg.indiana.edu/hypermail/linux/kernel/0806.3/1019.html > > Correct???? The need to do this goes out of the window if you're on a 64-bit OS. But, as far as I know, even on a 64-bit system and if the device has the "64-bit BAR capable" flag set, the BIOS still tries to assign PCI BARs below 4GB. The reason behind this is that some driver software still does not handle 64-bit BARs properly. Just what I've heard. > > >> Writing/changing BAR register value through device driver, will >> propagate till PCI root controller ? >> Can setpci command be used for this ? >> >> Any link or reference will be helpful. >> >> Thanking in advance, >> Yogeshwar > > > -- > Regards, > Peter Teoh > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx > Please read the FAQ at http://kernelnewbies.org/FAQ > > I'm very interested in getting to know more about this too. We've recently run into this problem at work, when trying to get a large number of our PCIE devices working on a single system. We can run out of physical address space if the BIOS allocates the BARs of all devices below 4GB. -- kthxbye -Mayank -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
