View source for EBC Exercise 19 DSS2 and sysfs

[[Category:ECE497]]
{{YoderHead}}

{{EBC3.2}}Here are some example DSS2 sysfs commands that run on the Beagle xM running the 3.2 kernel. (No BeagleBone Black version yet.)

Play around and see what you can learn.

=== Framebuffers ===

The framebuffers are in '''/sys/class/graphics/'''.
 beagle$ '''ls -F /sys/class/graphics/'''
 fb0@  fb1@  fb2@  fbcon@
 beagle$ '''cd /sys/class/graphics/fb0'''
 beagle$ '''ls -F'''
 bits_per_pixel  dev      modes            pan        rotate_type  subsystem@
 blank           device@  name             phys_addr  size         uevent
 console         mirror   overlays         power/     state        virt_addr
 cursor          mode     overlays_rotate  rotate     stride       virtual_size

===  Overlays, Managers and Displays ===
The overlays, managers and displays are in '''/sys/devices/platform/omapdss/'''
 beagle$ '''cd /sys/devices/platform/omapdss/'''
 beagle$ '''ls -F'''
 display0@  manager1/                     overlay0/  subsystem@
 display1@  microamps_requested_vdda_dac  overlay1/  uevent
 driver@    microamps_requested_vdds_dsi  overlay2/
 manager0/  modalias                      power/

 beagle$ '''cd overlay0'''
 beagle$ '''ls -F'''
 enabled       input_size  name         position
 global_alpha  manager     output_size  screen_width
 beagle$ '''cat position'''
 0,0
 beagle$ '''cat manager'''
 lcd
 beagle$ '''cat output_size'''
 640,480

=== Investigate mplayer ===

Load Big Buck Bunny.  This took some 3 minutes for me.
 beagle$ '''cd exercises/gstreamer'''
 beagle$ '''git clone git://github.com/MarkAYoder/esc-media.git'''
 beagle$ '''cd esc-media'''

Now, start Big Buck Bunny and discover how it uses DSS
 beagle$ '''mplayer BigBuckBunny_640x360.m4v'''
 beagle$ '''cd /sys/devices/platform/omapdss'''
 beagle$ '''ls'''
 beagle$ '''cd overlay0'''
 beagle$ '''cat enabled'''
Repeat for overlay1 and 2, Which are being used? cd to it.

=== Play with scale and position ===

 beagle$ '''cd /sys/devices/platform/omapdss/overlay2'''
 beagle$ '''cat position'''
 beagle$ '''echo 100,100 >  position'''
 beagle$ '''cat output_size'''
 beagle$ '''echo 320,400 > output_size'''

Try transparency
 beagle$ '''echo 127 > global_alpha'''
 beagle$ '''cd ../manager0'''
 beagle$ '''echo 1 > alpha_blending_enabled'''
 beagle$ '''echo 1 > trans_key_enabled'''
 beagle$ '''echo 65535 > trans_key_value'''
Caution:  You may have to disable an overlay before changing some values.
 beagle$ '''echo “0” > $ovl0/enabled'''

=== <span style="color:green">Assignment</span> ===
<span style="color:green">Note what you have learned in a short memo.</span>

==== Challenge ====

Can you get mplayer to appear in two windows?

{{YoderFoot}}