On Mon, Feb 18, 2008 at 11:18:48AM -0800, Roland Dreier wrote: > > > AFAIK mapping PCI memory WB is not allowed, so WC is really our only > > > choice. > > > afaik that depends on the BAR being prefetchable or not. > > In my case the BAR is prefetchable.
Even if the BAR is prefetchable, on some platforms mapping MMIO space as WB can cause bad results like machine check etc. > > (and by your argument, ioremap_cached() would not be useful, and since > that was, until > > 2.6.25-rc1, the default behavior for ioremap(), would have caused massive > problems) > > I'm not sure what ioremap_cached() would really do in my case, since > the MTRRs for PCI memory are set to UC, so without monkeying with MTRR > contents (which can't really be done safely) the only choices we have > are leaving the mapping as UC or using PAT to get WC. thanks, suresh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
