Openmoko Bug #2243: [Xglamo] some motion events are thrashed

[Openmoko Public Trac]

#2243: [Xglamo] some motion events are thrashed
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 Reporter:  Richard.Kralovic  |          Owner:  openmoko-devel
     Type:  enhancement       |         Status:  new           
 Priority:  normal            |      Milestone:                
Component:  unknown           |        Version:  FSO-MS2       
 Severity:  normal            |       Keywords:  Xglamo        
 Haspatch:  1                 |      Blockedby:                
Estimated:                    |    Patchreview:                
 Blocking:                    |   Reproducible:                
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Comment(by arhuaco):

 Warning: Sleepy human typing. Grammar glitches expected.

 Hi there.

 I do not know about xglamo but in s3c2410_ts.c this buffer does not have
 to be that big.

 I will explain what should happen in case it helps you with what you are
 trying to track.

 In event_send_timer_f (timer callback) a call to
 s3c2410_ts_start_adc_conversion is issued right before reporting the
 coordinate to the input layer. This call tells the hardware to start a
 conversion and it should take it about 0.45ms(IIRC) with current settings.
 Since event_send_timer_f is a timer callback ts_input_report is not
 allowed to sleep.

 Thus we get something like...

 event_send_timer_f:
 - schedules hardware conversion
 - gets coordinates from buffer
 - reports to the input layer
 ... do more things if we have more data in the FIFO but return ASAP.

 At some moment the stylus_action IRS should be called, most likely after
 we have already sent the previous event to the input layer.

 Unless you are actually getting the "event_send_timer_f failed" message in
 dmesg things should be OK on s3c2410_ts.c side. I don't think it will
 happen but if you ever get this message it is a bug ...  if you get this
 bug please let us know.

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2243#comment:2>
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