From: Sean Paul <seanpaul@xxxxxxxxxxxx> Drivers shouldn't be using these values, add a TODO so someone removes them. Changes in v2: - Add drm_display_mode.vrefresh removal (Ville) - Add Sam's R-b and bonus points Changes in v3: - Add hsync removal todo item (Daniel) - Change vrefresh wording to make removal less optional Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Suggested-by: Daniel Vetter <daniel@xxxxxxxx> Reviewed-by: Daniel Vetter <daniel@xxxxxxxx> Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx> Bonus-points-awarded-by: Sam Ravnborg <sam@xxxxxxxxxxxx> Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> --- This time with feeling. Documentation/gpu/todo.rst | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 38360ede12215..f67c84b92873c 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -262,6 +262,34 @@ 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. + +Once all instances of vrefresh have been converted, remove vrefresh from +drm_display_mode to avoid future use. + +Contact: Sean Paul + +Remove drm_display_mode.hsync +----------------------------- + +We have drm_mode_hsync() to calculate this from hsync_start/end, since drivers +shouldn't/don't use this, remove this member to avoid any temptations to use it +in the future. If there is any debug code using drm_display_mode.hsync, convert +it to use drm_mode_hsync() instead. + +Contact: Sean Paul + Core refactorings ================= -- Sean Paul, Software Engineer, Google / Chromium OS
