From: Luis R. Rodriguez Date: Tue, 26 May 2015 08:28:12 +0000 (+0200) Subject: x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages X-Git-Tag: omap-for-v4.2/fixes-rc1^2~170^2^2~14^2~5 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f9e897353fcb99effd6eff22f7b464f8e2a659a;p=pandora-kernel.git x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages As part of the effort to phase out MTRR use document write-combining MTRR effects on pages with different non-PAT page attributes flags and different PAT entry values. Extend arch_phys_wc_add() documentation to clarify power of two sizes / boundary requirements as we phase out mtrr_add() use. Lastly hint towards ioremap_uc() for corner cases on device drivers working with devices with mixed regions where MTRR size requirements would otherwise not enable write-combining effective memory types. Signed-off-by: Luis R. Rodriguez Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Antonino Daplas Cc: Borislav Petkov Cc: Brian Gerst Cc: Daniel Vetter Cc: Dave Airlie Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jean-Christophe Plagniol-Villard Cc: Jonathan Corbet Cc: Juergen Gross Cc: Linus Torvalds Cc: Mel Gorman Cc: Peter Zijlstra Cc: Suresh Siddha Cc: Thomas Gleixner Cc: Tomi Valkeinen Cc: Ville Syrjälä Cc: Vlastimil Babka Cc: linux-fbdev@vger.kernel.org Link: http://lkml.kernel.org/r/1430343851-967-3-git-send-email-mcgrof@do-not-panic.com Link: http://lkml.kernel.org/r/1432628901-18044-10-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed