On Tue, Jan 29, 2019 at 11:15:51AM -0500, Sean Paul wrote:
From: Sean Paul seanpaul@chromium.org
Suggested-by: Daniel Vetter daniel@ffwll.ch Signed-off-by: Sean Paul seanpaul@chromium.org
Documentation/gpu/todo.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 38360ede12215..7fc30380eaf6c 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -262,6 +262,21 @@ As a reference, take a look at the conversions already completed in drm core.
Contact: Sean Paul, respective driver maintainers
+Convert direct mode.vrefresh accesses to use drm_mode_vrefresh() +----------------------------------------------------------------
+drm_display_mode.vrefresh isn't guaranteed to be populated. As such, using it +is risky and has been known to cause div-by-zero bugs. Fortunately, drm core +has helper which will use mode.vrefresh if it's !0 and will calculate it from +the timings when it's 0.
+Use simple search/replace, or (more fun) cocci to replace instances of direct +vrefresh access with a call to the helper. Check out +https://lists.freedesktop.org/archives/dri-devel/2019-January/205186.html for +inspiration.
I would suggest just nuking mode.vrefresh entirely because we don't want to risk drm_mode_vrefresh() returning some stale value.
+Contact: Sean Paul
Core refactorings
-- Sean Paul, Software Engineer, Google / Chromium OS
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