On Thu, 2015-07-23 at 00:42 -0600, Jan Beulich wrote: > > > > > > On 22.07.15 at 20:06, <toshi.k...@hp.com> wrote: > > Add comments to the cachemode translation tables to clarify that > > the default values are set as minimal supported mode, which are > > necessary to handle WC and WT fallback to UC- when they are not > > enabled. > > Wait - shouldn't WT fall back to UC (so to not be affected by WC > MTRR settings)?
Well, when MTRR is set to WC, WT will become UC. So, it is not safe to start with. I know Luis is driving to support UC. When UC can be used for both regular memory and IO memory, yes, it can be changed to fall back to UC. At this point, however, UC cannot be set to regular memory. See reserve_ram_pages_type(). Thanks, -Toshi -- 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/
