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

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==Get prepared==
This section focuses on debug display driver issue on rel-28.x BSP.<br>
Drivers of tegra display controller are under kernel source: https://developer.nvidia.com/embedded/downloads <br>
'''For T210(TX1)''' <br>
kernel/display/drivers/video/tegra/dc/ <br>
'''For T186(TX2).''' Note that TX2 still uses driver code of T210. <br>
kernel/t18x/drivers/video/tegra/dc <br>
*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  #unblank display
*Print out display kernel related message
dmesg |grep tegradc
** Display is not be able to up. Moreover, system is not able to up.(Fixed after rel-28.2)

Latest revision as of 01:28, 10 January 2018