Openmoko Bug #1841: white screen of death (WSOD) after resume

Openmoko Public Trac bugs at
Tue Dec 9 15:48:59 CET 2008

#1841: white screen of death (WSOD) after resume
 Reporter:  Rorschach  |          Owner:  openmoko-devel
     Type:  defect     |         Status:  new           
 Priority:  highest    |      Milestone:                
Component:  unknown    |        Version:  GTA02v5       
 Severity:  critical   |       Keywords:  wsod,resume   
 Haspatch:  0          |      Blockedby:                
Estimated:             |    Patchreview:                
 Blocking:             |   Reproducible:  always        

Comment(by andy):

 > There are other reports of
 > WSOD not being dependent on going to deep_suspend mode at all
 > (and thus this patch shouldn't be able to help there).

 No Harald's patches did in fact push the LCM in deep suspend on
 framebuffer blanking:;a=commitdiff;h=f9e5eb98527feda1937f87d93a5b6dd6322baf83;hp=0e7b63e010904140cc39fe98a5d8abd3de7e4f0f

 +       case FB_BLANK_POWERDOWN:
 +               jbt6k74_enter_state(jbt, JBT_STATE_DEEP_STANDBY);
 +               break;

 and the report is from before Nicolas' patch, but after Harald's stuff, so
 that bug is not evidence of WSOD without deep sleep on jbt6k74 I think you
 find.  It is expected Nicolas' patch solves that bug report too.

 While there are no further reports of WSOD from several people running
 just Nicolas' fix, and they definitely had devices that were prone to it,
 I would suspect a WSOD you observed can be something else, maybe related
 to stable branch suspend / resume.

 For example if stable branch resume fails with backlight up but Glamo /
 LCM resume not having happened for unrelated reasons (since stable suspend
 / resume is known to be busted by potential races).  But I didn't read yet
 about "occasional" or "rare" WSOD from testers of Nicolas' patch, but that
 it was completely gone.

 If you're interested to go further into that, an idea would be not to use
 suspend but to reduce the framebuffer blanking timeout to a few seconds
 and repeatedly tap the touchscreen to keep bringing it back and see if you
 ever get a WSOD (using Nicolas' patches).

 On andy-tracking we already hard-reset the Glamo on resume, and I never
 ever saw a sticky WSOD by using reset button on debug board: in both cases
 there is no power cycling just hard reset.  So I don't think zeroing the
 Glamo LCM bus is involved in WSOD avoidance, but it can make sense on
 leakage grounds during suspend.

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