Ubuntu
linux package

  1. Xenial (16.04)
  2. Bug #1574814
  3. Comment #16

Comment 16 for bug 1574814

Revision history for this message
dann frazier (dannf) wrote : Re: ThunderX: soft lockup in cursor_timer_handler() Edit

I used ftrace to do some duration measuring of the timer function fb_flashcursor(). I noticed several places where this timer takes around 98 ms to complete. This time seems to be due to multiple calls to __memcpy_toio() in ast_dirty_update():

 for (i = y; i <= y2; i++) {
  /* assume equal stride for now */
  src_offset = dst_offset = i * afbdev->afb.base.pitches[0] + (x * bpp);
  memcpy_toio(bo->kmap.virtual + src_offset, afbdev->sysram + src_offset, (x2 - x + 1) * bpp);

My theory is that this is causing mod_timer() to block on the other CPU, resulting in the soft lockup.

Also - I built a custom d-i using pristine 4.6-rc7, and I am able to easily reproduce this. I think the next step here is to report this to upstream.