#11041 NORM 1.75-so: XO-1.75 accelerometer may hang

Zarro Boogs per Child bugtracker at laptop.org
Wed Jul 20 22:16:21 EDT 2011

#11041: XO-1.75 accelerometer may hang
           Reporter:  Quozl          |       Owner:  saadia                           
               Type:  defect         |      Status:  new                              
           Priority:  normal         |   Milestone:  1.75-software                    
          Component:  kernel         |     Version:  Development build as of this date
         Resolution:                 |    Keywords:  XO-1.75, accelerometer           
        Next_action:  test in build  |    Verified:  0                                
Deployment_affected:                 |   Blockedby:                                   
           Blocking:                 |  

Comment(by Quozl):

 Replying to [comment:7 wad]:
 > Hmm.   Interesting how dropping the bit rate to 25% produced a drop in
 access frequency to 5%.   Are we sure something else didn't change as well

 I'm not concerned; the range change doesn't seem wrong.  I've not seen the
 patch yet, and would like to.  But my tests of the bit rate before the
 patch, in conjunction with other system loads, suggested that the bit rate
 was limited by the CPU or memory, not the bus.  Now, with a slower bus,
 the bottleneck has merely moved to the bus.

 My test of read rate is repeated reads of the sysfs position file,
 effectively a test of calling lis3lv02d_get_xyz() in the driver, and this
 looks like it causes a read of six bytes from the device register address
 0x28 over i2c.  So there's a multiplier.

Ticket URL: <http://dev.laptop.org/ticket/11041#comment:8>
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