path: root/Documentation/fb
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authorMaxime Ripard <>2019-06-19 12:17:51 +0200
committerMaxime Ripard <>2019-06-19 12:17:51 +0200
commit1bf4e09227c345e246062285eba4b8fe660e512e (patch)
tree45396ee8fa752b77e08db4c2ae3be1f1c21dab2b /Documentation/fb
parent3aeeb13d899627fe2b86bdbdcd0927cf7192234f (diff)
drm/modes: Allow to specify rotation and reflection on the commandline
Rotations and reflections setup are needed in some scenarios to initialise properly the initial framebuffer. Some drivers already had a bunch of quirks to deal with this, such as either a private kernel command line parameter (omapdss) or on the device tree (various panels). In order to accomodate this, let's create a video mode parameter to deal with the rotation and reflexion. Reviewed-by: Noralf Trønnes <> Signed-off-by: Maxime Ripard <> Link:
Diffstat (limited to 'Documentation/fb')
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/fb/modedb.txt b/Documentation/fb/modedb.txt
index 16aa08453911..52418c6dbfc4 100644
--- a/Documentation/fb/modedb.txt
+++ b/Documentation/fb/modedb.txt
@@ -51,6 +51,18 @@ To force the VGA output to be enabled and drive a specific mode say:
Specifying the option multiple times for different ports is possible, e.g.:
video=LVDS-1:d video=HDMI-1:D
+Options can also be passed after the mode, using commas as separator.
+ Sample usage: 720x480,rotate=180 - 720x480 mode, rotated by 180 degrees
+Valid options are:
+ - reflect_x (boolean): Perform an axial symmetry on the X axis
+ - reflect_y (boolean): Perform an axial symmetry on the Y axis
+ - rotate (integer): Rotate the initial framebuffer by x
+ degrees. Valid values are 0, 90, 180 and 270.
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What is the VESA(TM) Coordinated Video Timings (CVT)?