VPSS / FBDEV Usage

yihe,

 Thanks for the answer above.  This does indeed seem to work.  So a follow up question. 

 We have set an LCD VOUT0 display off up display1 to be 800x480 RGB888 and the correct timing for the display. 

 When I open up fbo and use the IOCTL command   FBIOGET_FSCREENINFO it lists the screen resolution has 1280x720 with 32 bits per pixel.  Do I also need to configure fbo using IOCTL commands to match the device screen resolution of the device or are these independent?

Craig

Craig,

Yes, please use FBIOPUT_VSCREENINFO IOCTl to set the proper xres/yres/xres_virtual/yres_virtual, bpp and other stuffs. There is a fbdev example code inside the PSP package. You can refer that file

Regards,

yihe

yihe,

Just so I am clear.  We not only have to setup the resolution and timing for Display1, but also we have to setup the frame buffer to match.  We are doing the following to drive our LCD display.

 -- Connect fbo to display1 to drive VOUTO

echo 1:dvo2 > /sys/devices/platform/vpss/graphics0/nodes

 -- Setup the timing correct for our display

echo 148500,1920/88/148/44,1080/4/36/5,1 > /sys/devices/platform/vpss/display1/timings

 -- Setup the correct mode for the output

echo single,rgb888 > /sys/devices/platform/vpss/display1/output

 -- Then run using the IOCTL FBIOPUT_VSCREENINFO we would setup the correct:

- Screen resolution (800x480), bpp, Pixel clk, etc..

 Not sure if I understand why we need to setup display1 and the FBO? 

Thanks for the help/explanation

Craig

Hi,

I think you are confused with Vout0 and on-chip HDMI. Here is the mapping for the Vout and encoders.

Vout[0] --> DVO2 encoder.

Vout[1] --> on-chip HDMI encoder.

So if you are trying to us DVO2 that is named as display1 under the linux sysfs and you should set timings on that. If you are trying on-chip HDMI of Vout[1] you should use display0 for set timings. Hope this clears the confusion. By default graphics 0 is connected to onchip HDMI (Vout[1]).

Regards,

Hardik Shah

Craig,

Do you want to have 1920x1080P60 resolution or 800x480 resolution?

1. if you want to have 1920x1080P60, you do not need the following since by default DVO2(VOUT0/Display1) is set to 1080P60.

• no need to do this: echo 148500,1920/88/148/44,1080/4/36/5,1 > /sys/devices/platform/vpss/display1/timings

• IOCTL FBIOPUT_VSCREENINFO to set proper parameter

2. if you want to have 800x480 resolution,

•   set the propoer timing parameter through /sys/devices/platform/vpss/display1/timings
• IOCTL FBIOPUT_VSCREENINFO to set proper paramter

Regards,

yihe

Yihe,

Thanks for the response.  I have been out of  town, so just getting back to this.  We are using a LCD display at 800x480 (Nec - NL8048BC19 with a FIN3885 bus driver between the integra and the display).  We are having issues getting any thing to show up on the LCD display.  We believe we have the timing for the display setup correctly, but don't see any data.  We are using the sysclass interface to configure the display and  are doing the following commands:

//

// Setup Timing

//

echo 0 > /sys/devices/platform/vpss/graphics0/enabled

echo 0 > /sys/devices/platform/vpss/display1/enabled

echo 32256,800/112/112/1,480/20/25/1,1 > /sys/devices/platform/vpss/display1/timings

echo 1 > /sys/devices/platform/vpss/display1/enabled

echo 1 > /sys/devices/platform/vpss/graphics0/enabled

//

//  Change the mode to RGB 888

//

echo 0 > /sys/devices/platform/vpss/display1/enabled

echo single,rgb888 > /sys/devices/platform/vpss/display1/output

echo 1 > /sys/devices/platform/vpss/display1/enabled

//

//  Switch the node

//

echo 0 > /sys/devices/platform/vpss/graphics0/enabled

echo 1:dvo2 > /sys/devices/platform/vpss/graphics0/nodes

echo 1 > /sys/devices/platform/vpss/graphics0/enabled

We are also setting up FB0 to be the correct resolution for the display (800x480) and bits per pixel to 24.  So a few questions:

1. We are not sure what sync mode  to use for the RGB (single/double/doublediscrete/triple/triplediscrete).  Can you shed some light on what each of these sync modes are or point us to where they are defined?

1. Do we need to configure more settings in the FB0 to match our display?

1. Is there anything else you can point us to look at to further try and isolate where the issue may be?

Thanks,

Craig

Yihe,

1)      The panel takes a discrete data enable single (DE).   We are using the VOUT[0]_AVID signal for this purpose.  I have attached the LCD display specification for reference.

2)      The panel takes a RGB24 bit signal

3)      We believe the backlight and power for the LCD is setup correctly. 

4)      Per your response, is seems like we should be using triplediscrete sync

Thanks for any help you can provide…

Craig

3884.7.0 NL8048BC19-02 wide.pdf

Forgot to attach the display......