From: Chris Wilson Date: Wed, 22 May 2013 16:08:06 +0000 (+0100) Subject: drm/i915: Workaround incoherence with fence updates on Valleyview X-Git-Tag: v3.11-rc1~65^2~105^2~58 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2dc8aae06d53458dd3624dc0accd4f81100ee631;p=pandora-kernel.git drm/i915: Workaround incoherence with fence updates on Valleyview In commit 25ff1195f8a0b3724541ae7bbe331b4296de9c06 Author: Chris Wilson Date: Thu Apr 4 21:31:03 2013 +0100 drm/i915: Workaround incoherence between fences and LLC across multiple CPUs we introduced an empirical workaround for memory corruption when using fences from multiple CPUs. At the time, we did not have any results for Valleyview, so the presumption was that it was limited to recent generations using LLC. Now we have evidence that Valleyview also suffers incoherence and requires a similar but different workaround. For Valleyview, the wbinvd instruction is insufficient and we require the serialising register write per-CPU. Conversely, that serialising register write is not enough for SNB/IVB/HSW. To compromise and keep the code relatively clean, employ both serialisation techniques in the same workaround. Reported-by: Jon Bloomfield Tested-by: Jon Bloomfield Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=62191 Signed-off-by: Chris Wilson Signed-off-by: Daniel Vetter --- Reading git-diff-tree failed