#9350 HIGH 10.1.3: xrandr screen rotation support

[Zarro Boogs per Child]

#9350: xrandr screen rotation support
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           Reporter:  dsd              |       Owner:  jnettlet                         
               Type:  defect           |      Status:  assigned                         
           Priority:  high             |   Milestone:  10.1.3                           
          Component:  x window system  |     Version:  Development build as of this date
         Resolution:                   |    Keywords:                                   
        Next_action:  design           |    Verified:  0                                
Deployment_affected:                   |   Blockedby:                                   
           Blocking:  10229            |  
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Comment(by jnettlet):

 I think we need some clarification on terminology and functionality.

 1) Current shipped openchrome driver is not RandR 1.2 compliant.  The
 SWRandR is a poorly termed feature that disables Hardware Acceleration on
 the card and instead creates a framebuffer in system memory that is
 rendered by the cpu.  This is generally a work around for cards that don't
 have good 2d acceleration support, and is very cpu intensive.  This
 feature rotates the screen incorrectly, and yes it can be worked around
 easily enough in the driver.
 2) The new "testing" openchrome driver implements full Randr 1.2
 functionality which has the added functionality of getting rotation
 implemented for "free".  This system uses XAA and XV acceleration in the
 "normal" 0 rotated position and uses software compositing for rotated
 positions.  It is really slow because the software compositing fallback is
 horrible and nobody really wants to fix it.  To speed this up we would
 need to implement an updated drm module that can talk to the 3d engine in
 the Chrome9 hardware properly.  It was decided that any new features are
 going in 2.6.35 and newer so this won't be happening.  This feature set
 rotates the screen properly.
 3)  Someone can dig further into the code and hardware to figure out why
 the 2d hardware functionality of the VX855 fails with a resolution of
 1200x900.  It appears to be due to the alignment of that resolution, but
 "adjusting" the resolution to align properly causes the dcon to fail to
 raster the image.

 I hope this helps in making a  decision to be made on the proper path
 forward.

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Ticket URL: <http://dev.laptop.org/ticket/9350#comment:53>
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