Le 21/06/2013 07:00, H. Peter Anvin a écrit : > An awful lot of drivers, mostly DRI drivers, are still mucking with > MTRRs directly as opposed to using ioremap_wc() or similar interfaces. > In addition to the architecture dependency, this is really undesirable > because MTRRs are a limited resource, whereas page table attributes are not. > > Furthermore, this perpetuates the need for the horrific hack known as > "MTRR cleanup". > > What, if anything, can we do to clean up this mess? > > -hpa >
The first network driver that used ioremap_wc() back in 2008 (myri10ge) had to keep using MTRR because ioremap_wc() silently falls back to ioremap_nocache() when PAT is disabled. I asked about this in https://lkml.org/lkml/2008/5/31/42 and there was some talk about putting the MTRR addition in the nocache fallback path but I guess nobody implemented the idea. Brice -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
