Difference between revisions of "Jetson TX2/28 Display debug"

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(Tips)
(Tips)
Line 19: Line 19:
 
  2. set use_fallback = true; in tegra_edid_get_monspecs() under edid.c.
 
  2. set use_fallback = true; in tegra_edid_get_monspecs() under edid.c.
 
  3. fill in the known EDID to default_720p_edid[256].
 
  3. fill in the known EDID to default_720p_edid[256].
* Do I hit underflow? (red screen or blank line flicker)
+
*Do I hit underflow? (red screen or blank line flicker)
 
  sudo cat /sys/kernel/debug/tegradc.0/stats
 
  sudo cat /sys/kernel/debug/tegradc.0/stats
 
  underflows: 35
 
  underflows: 35
Line 31: Line 31:
 
  sudo  echo 0 > /sys/class/graphics/fb0/blank
 
  sudo  echo 0 > /sys/class/graphics/fb0/blank
  
*Other issues
+
*Print out display kernel related message
  dmesg |grep tegradc #print out display kernel related message
+
  dmesg |grep tegradc
  
 
==Issues==
 
==Issues==

Revision as of 23:18, 8 January 2018

Get prepared

This section focuses on debug display driver issue on rel-28.x release.
Drivers of tegra display controller are under kernel source: https://developer.nvidia.com/embedded/downloads
Location:
For T210(TX1)
kernel/display/drivers/video/tegra/dc/
For T186(TX2). Note that TX2 still uses driver code of T210.
kernel/t18x/drivers/video/tegra/dc

Tips

  • Print current mode in dc
sudo cat /sys/kernel/debug/tegradc.X/mode  #X=0,1,2.
  • Print current mode in fbcon
sudo cat /sys/class/graphics/fb0/mode  #if more than one fb, just change the fbX to whatever you want.
  • Capture edid
sudo cat /sys/kernel/debug/tegradc.X/edid  #X=0,1,2.
  • Forcing edid
1. Prepare a known 256byte EDID.
2. set use_fallback = true; in tegra_edid_get_monspecs() under edid.c.
3. fill in the known EDID to default_720p_edid[256].
  • Do I hit underflow? (red screen or blank line flicker)
sudo cat /sys/kernel/debug/tegradc.0/stats
underflows: 35
underflows_a: 143
underflows_b: 0
underflows_c: 0
  • Blank/Unblank window/display
sudo  echo 4 > /sys/class/graphics/fb0/blank  #blank display and power down
sudo  echo 1 > /sys/class/graphics/fb0/blank  #blank display and show the background color
sudo  echo 0 > /sys/class/graphics/fb0/blank
  • Print out display kernel related message
dmesg |grep tegradc

Issues