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| author | Sean Paul <seanpaul@chromium.org> | 2019-01-29 14:26:29 -0500 |
|---|---|---|
| committer | Sean Paul <seanpaul@chromium.org> | 2019-01-31 13:01:26 -0500 |
| commit | d60ea31a87314eb7bea0b2dcbd36cf12bdf9ac0d (patch) | |
| tree | e89eef22c612d750cc4db5125cc486c0790816f9 /Documentation/gpu | |
| parent | 3dadbd2957eb8dad8e9ca0c639307a732e564bf7 (diff) | |
| download | lwn-d60ea31a87314eb7bea0b2dcbd36cf12bdf9ac0d.tar.gz lwn-d60ea31a87314eb7bea0b2dcbd36cf12bdf9ac0d.zip | |
drm/TODO: Add drm_display_mode.hsync/vrefresh removal
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@linux.intel.com>
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Bonus-points-awarded-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190129192637.73296-1-sean@poorly.run
Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/todo.rst | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index a1d91ca7f65c..cda4a37a02f0 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -272,6 +272,34 @@ no one knows what that means) since underneath they just use dma_alloc_coherent. Contact: Laurent Pinchart, Daniel Vetter +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 ================= |