#9561 NORM 1.5-F11: mouse cursor moves after suspend/resume

[Zarro Boogs per Child]

#9561: mouse cursor moves after suspend/resume
--------------------------------+-------------------------------------------
           Reporter:  pgf       |       Owner:  dsaxena                          
               Type:  defect    |      Status:  new                              
           Priority:  normal    |   Milestone:  1.5-F11                          
          Component:  kernel    |     Version:  Development build as of this date
         Resolution:            |    Keywords:                                   
        Next_action:  diagnose  |    Verified:  0                                
Deployment_affected:            |   Blockedby:                                   
           Blocking:            |  
--------------------------------+-------------------------------------------

Comment(by wmb at firmworks.com):

 > "When read: Graphical Display Vertical Line Number"

 That is probably the current scan line that is being read from memory.
 Useful info for preventing glitches due to changing data while the display
 engine is fetching it.

 One workaround would be for chrome to shadow the cursor position in
 scratch registers that viafb can read.  CRT registers 49-4f would do.  The
 manual lists them as "reserved" on page 20 (pdf page 27) but the top of
 page 38 (pdf page 45) suggests that they are scratch registers.  I have
 verified in OFW that you can write to them and read them back.  So they
 would serve as a back channel between chrome and viafb.

 Yes, I know it's a hack.

-- 
Ticket URL: <http://dev.laptop.org/ticket/9561#comment:7>
One Laptop Per Child <http://laptop.org/>
OLPC bug tracking system