3.9.7. DSS Applications

DSS applications are omapdrm based. These will demonstrate the clone mode, extended mode, overlay window, z-order and alpha blending features. To demonstrate clone and extended mode, HDMI display must be connected to board.

3.9.7.1. Running DSS Applications

These applications require the supported mode information of connected displays and plane ids. One can get these information by running the modetest application in the filesystem.

# modetest

3.9.7.1.1. Running drmclone

This displays the same test pattern on both LCD and HDMI (clone). Overlay windows are also displayed on LCD. To test clone mode, execute the following command:

# drmclone -l <lcd_w>x<lcd_h> -p <plane_w>x<plane_h>:<x>+<y> -h <hdmi_w>x<hdmi_h>

For example:

# drmclone -l 1280x800 -p 320x240:0+0 -h 640x480

We can change position of overlay window by changing x+y values. eg. 240+120 will show @ center

3.9.7.1.2. Running drmextended

This displays different test pattern on LCD and HDMI. Overlay windows are also displayed on LCD. To test extended mode, execute the following command:

# drmextended -l <lcd_w>x<lcd_h> -p <plane_w>x<plane_h>:<x>+<y> -h <hdmi_w>x<hdmi_h>

For example:

# drmextended -l 1280x800 -p 320x240:0+0 -h 640x480

3.9.7.1.3. Running drmzalpha

This displays alpha blended patters on the given display. To use it the following paramters must be specified:

Z-order:

It determines, which overlay window appears on top of the other.

Range: 0 to 3

  • lowest value for bottom

  • highest value for top

Alpha Blend:

It determines transparency level of image as a result of both global alpha & pre multiplied alpha value.

Global alpha range: 0 to 255

  • 0 - fully transparent

  • 127 - semi transparent

  • 255 - fully opaque

Pre multipled alpha value: 0 or 1

  • 0 - source is not premultiply with alpha

  • 1 - source is premultiply with alpha

To test drmzalpha, execute the following command:

# drmzalpha -s <crtc_w>x<crtc_h> -w <plane1_id>:<z_val>:<glo_alpha>:<pre_mul_alpha> -w <plane2_id>:<z_val>:<glo_alpha>:<pre_mul_alpha>

For example:

# drmzalpha -s 1280x800 -w 19:1:255:1 -w 20:2:255:1