Provided by: xserver-xorg-core_21.1.4-2ubuntu1_amd64 bug


       modesetting - video driver for framebuffer device


       Section "Device"
         Identifier "devname"
         Driver "modesetting"
         BusID  "pci:bus:dev:func"


       modesetting  is an Xorg driver for KMS devices.  This driver supports TrueColor visuals at
       framebuffer depths of  15,  16,  24,  and  30.  RandR  1.2  is  supported  for  multi-head
       configurations.  Acceleration  is available through glamor for devices supporting at least
       OpenGL ES 2.0 or OpenGL 2.1.  If glamor is not enabled, a shadow framebuffer is configured
       based  on  the  KMS  drivers'  preference (unless the framebuffer is 24 bits per pixel, in
       which case the shadow framebuffer is always used).


       The modesetting driver supports all hardware where a KMS driver is available.  modesetting
       uses the Linux DRM KMS ioctls and dumb object create/map.


       Please  refer to xorg.conf(5) for general configuration details.  This section only covers
       configuration details specific to this driver.

       For this driver it is not required to specify modes in the screen section  of  the  config
       file.   The  modesetting  driver can pick up the currently used video mode from the kernel
       driver and will use it if there are no video modes configured.

       For PCI boards you might have to add a BusID line to the Device section.  See above for  a
       sample line.

       The following driver Options are supported:

       Option "SWcursor" "boolean"
              Selects software cursor.  The default is off.

       Option "kmsdev" "string"
              The framebuffer device to use. Default: /dev/dri/card0.

       Option "ShadowFB" "boolean"
              Enable or disable use of the shadow framebuffer layer.  Default: on.

       Option "DoubleShadow" "boolean"
              Double-buffer  shadow updates. When enabled, the driver will keep two copies of the
              shadow framebuffer. When the  shadow  framebuffer  is  flushed,  the  old  and  new
              versions  of the shadow are compared, and only tiles that have actually changed are
              uploaded to the device. This is an optimization for server-class GPUs with a remote
              display  function  (typically  VNC),  where  remote  updates  are  triggered by any
              framebuffer write, so minimizing the amount of  data  uploaded  is  crucial.   This
              defaults to enabled for ASPEED and Matrox G200 devices, and disabled otherwise.

       Option "AccelMethod" "string"
              One of "glamor" or "none".  Default: glamor.

       Option "PageFlip" "boolean"
              Enable DRI3 page flipping.  The default is on.

       Option "VariableRefresh" "boolean"
              Enables  support  for  enabling  variable  refresh  on  the  Screen's CRTCs when an
              suitable application is flipping via the Present extension.
              The default is off.

       Option "AsyncFlipSecondaries" "boolean"
              Use async flips for secondary video outputs on multi-display setups.  If  a  screen
              has multiple displays attached and DRI3 page flipping is used, then only one of the
              displays will have its page flip synchronized to vblank for tear-free presentation.
              This  is the display that is used for presentation timing and timestamping, usually
              the one covering the  biggest  pixel  area  of  the  screen.   All  other  displays
              ("Secondaries")  will  not  synchronize their flips. This may cause some tearing on
              these displays, but it prevents a permanent  or  periodic  slowdown  or  irritating
              judder  of  animations  if not all video outputs are running synchronized with each
              other and with the same refresh rate. There  is  no  perfect  solution  apart  from
              perfectly synchronized outputs, but this option may give preferrable results if the
              displays in a multi-display setup mirror or clone each other.  The default is off.

       Option "ZaphodHeads" "string"
              Specify the RandR output(s) to  use  with  zaphod  mode  for  a  particular  driver
              instance.  If you use this option you must use this option for all instances of the
              For example: Option "ZaphodHeads" "LVDS,VGA-0" will assign xrandr outputs LVDS  and
              VGA-0 to this instance of the driver.

       Option "UseGammaLUT" "boolean"
              Enable  or  disable  use  of the GAMMA_LUT property, when available.  When enabled,
              this option allows the driver to use gamma ramps with more entries, if supported by
              the  kernel.  By default, GAMMA_LUT will be used for kms drivers which are known to
              be safe for use of GAMMA_LUT.

       SEE ALSO
              Xorg(1), xorg.conf(5), Xserver(1), X(7)


       Authors include: Dave Airlie