aBUGSworstnightmare
Posts: 1492
Joined: Tue Jun 30, 2015 1:35 pm

Pixel desktop is not using full screen resolution

Sun Oct 16, 2016 11:59 am

Hi,
today I have a somehow special problem and don't know where to post it in the forum so I decided to use the 'advanced' thread.

My Raspberry is configured for using the 24bit DPI overlay (dpi24.dtbo). Basically, the display (CPT CLAA070WP03XG - Nexus 7 display) is working, but the PIXEL desktop is not using the full screen resolution.

I made a short test, running two OMXplayer instances and a picture slideshow (the images are 1280x800pixels)

Code: Select all

!/bin/bash
screen -dmS pic1 sh -c 'feh -Y -x -q -D 3 -B black -F -Z -z /home/pi/Pictures; exec bash'
screen -dmS vid3 sh -c 'omxplayer --win "640 440 1280 800" /home/pi/Videos/trailer_1080p.mov; exec bash'
screen -dmS vid2 sh -c 'omxplayer --win "0 0 640 360" /home/pi/Videos/trailer_1080p.mov; exec bash'
WP_20161016_12_44_54_Smart.jpg
Upper left OMXplayer window ("0 0 640 360") is perfectly aligned.
Note the gap on the left side of the screen with not PIXEL desktop.
WP_20161016_12_44_54_Smart.jpg (35.39 KiB) Viewed 4019 times
WP_20161016_12_45_07_Smart.jpg
OMXplayer window in lower right corner ("640 440 1280 800") is perfectly aligned too. Note the gap on the right side.
WP_20161016_12_45_07_Smart.jpg (25.14 KiB) Viewed 4019 times
As you can see from the pictures PIXEL is not using the whole display. I've made a screenshot with 'scrot', capturing the entire screen. The resulting image is only 1200x800 pixels.

Since OMXplayer is able to use the entire display I need to know why PIXEL is not able doing the same!
Here is my config.txt file:

Code: Select all

# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# set display orientation
display_rotate=3

# uncomment to force a console size. By default it will be display's size minus
# overscan.
framebuffer_width=1280
framebuffer_height=800

# Enable audio (loads snd_bcm2835)
dtparam=audio=on
gpu_mem=384


# ---------------------------------------------
# Enable DPI
# --------------------------------------------- 
enable_dpi_lcd=1

# ---------------------------------------------
# Make DPI default output
# ---------------------------------------------
display_default_lcd=1

# ---------------------------------------------
# custom HDMI mode
# https://www.raspberrypi.org/forums/viewtopic.php?p=613926#p613926
# https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=24679
# ---------------------------------------------
dpi_group=2
dpi_mode=87

#additional config settings
gpu_mem=392

# Uncomment some or all of these to enable the optional hardware interfaces
dtparam=i2c_arm=off
dtparam=spi=off

# Uncomment this to enable the lirc-rpi module
dtoverlay=dpi24.dtbo

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

# ---------------------------------------------
# DPI output format definitions
# https://www.raspberrypi.org/forums/viewtopic.php?p=628061#p628061
# DPI structure: https://www.raspberrypi.org/forums/viewtopic.php?p=617719#p617719
# ---------------------------------------------
# output_format:
#   1: DPI_OUTPUT_FORMAT_9BIT_666
#   2: DPI_OUTPUT_FORMAT_16BIT_565_CFG1
#   3: DPI_OUTPUT_FORMAT_16BIT_565_CFG2
#   4: DPI_OUTPUT_FORMAT_16BIT_565_CFG3
#   5: DPI_OUTPUT_FORMAT_18BIT_666_CFG1
#   6: DPI_OUTPUT_FORMAT_18BIT_666_CFG2
#   7: DPI_OUTPUT_FORMAT_24BIT_888
#
# rgb_order:
#   1: DPI_RGB_ORDER_RGB
#   2: DPI_RGB_ORDER_BGR
#   3: DPI_RGB_ORDER_GRB
#   4: DPI_RGB_ORDER_BRG
#
# output_enable_mode:
#   0: DPI_OUTPUT_ENABLE_MODE_DATA_VALID
#   1: DPI_OUTPUT_ENABLE_MODE_COMBINED_SYNCS
#
# invert_pixel_clock:
#   0: RGB Data changes on rising edge and is stable at falling edge
#   1: RGB Data changes on falling edge and is stable at rising edge
#
# hsync polarity: 
#   0: default for HDMI mode
#   1: inverted
#
# vsync polarity:
#   0: default for HDMI mode
#   1: inverted
#
# output_enable_polarity:
#   0: default for HDMI mode
#   1: inverted
#
# hsync phase:
#   0: rising edge
#   1: falling edge
#
# vsync phase:
#   0: rising edge
#   1: falling edge
#
# output_enable phase:
#   0: rising edge
#   1: falling edge
# ---------------------------------------------
dpi_output_format=458775

# ---------------------------------------------
# HDMI timing definitions
#https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=24679
# ---------------------------------------------
# hdmi_timings= <h_active_pixels>
#		  LCD module horizontal resolution
#
#               <h_sync_polarity>
# 		  0: active low
#		  1: active high
#
#               <h_front_porch> 
#		<h_sync_pulse>
#		<h_back_porch>
#		<v_active_lines>
#		  LCD module vertical resolution
#
#		<v_sync_polarity>
# 		  0: active low
#		  1: active high
#
#		<v_front_porch>
#		<v_sync_pulse>
#		<v_back_porch>
#
#		<v_sync_offset_a>
#		<v_sync_offset_b>
#		<pixel_rep>
#
#		<frame_rate>
#		  screen refrech rate (50/60Hz supported only!)#
#
#		<interlaced>
#
#		<pixel_freq>
#		  calculates as: <h_active_pixels> * <v_active_lines> * <frame_rate>
#
#		<aspect_ratio>
#		  HDMI_ASPECT_4_3 = 1
#		  HDMI_ASPECT_14_9 = 2
#		  HDMI_ASPECT_16_9 = 3
#		  HDMI_ASPECT_5_4 = 4
#		  HDMI_ASPECT_16_10 = 5
#		  HDMI_ASPECT_15_9 = 6
#		  HDMI_ASPECT_21_9 = 7
#		  HDMI_ASPECT_64_27 = 8
# ---------------------------------------------
hdmi_timings=800 1 0 16 64 1280 1 8 1 0 0 0 0 60 0 66800000 5
As you can see the display resolution I'm using is correct. I've configured a frame buffer of the same size (1280x800) in addition, but the effect: Borders left and right of PIXEL desktop, regardless is frame buffer is configured or not.

Any ideas/recommendations how to solve this?
By the way: made a clean install using latest image; update/upgrade/ etc. was all done before activating the overlay and custom dpi timing. Already using/tested a lot of displays using this approach but never saw this happen.

Rgds
Joerg

aBUGSworstnightmare
Posts: 1492
Joined: Tue Jun 30, 2015 1:35 pm

BUG in how Pixel handles the frame buffer / display resoluti

Mon Oct 17, 2016 7:18 pm

Hey there,

since nobody seems to be able to answer to this question I made some more tests this evening. To me it looks like there is a BUG in Pixel - handling of frame buffer is wrong! Every resolution that is bigger than 1200pixels gets truncated to 1200!

Here is how I tested this
Folder with full resolution picture: https://drive.google.com/drive/folders/ ... sp=sharing

In my config I'm using

Code: Select all

framebuffer_width=1280
framebuffer_height=760
This gives me a full screen image on my display. Testing the resolution with

Code: Select all

xdpyinfo | grep dimensions
gives a strange result:
My reported desktop is only 1200x760pixel!
result.png
result.png (15.99 KiB) Viewed 3901 times
Systeminfo in Kodi tells me it's 1280x760 ... so: how to fix this? The native resolution of my screen is 1280x800 btw ...

aBUGSworstnightmare
Posts: 1492
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pixel desktop is not using full screen resolution

Tue Oct 18, 2016 5:11 am

changing the frame buffer to

Code: Select all

framebuffer_width=1280
framebuffer_height=800
gives me 40 pixel wide black borders on left and right side.

Code: Select all

xdpyinfo | grep dimensions
now reports resolution to be 1200x800 pixel
chgframeb.png
chgframeb.png (27.19 KiB) Viewed 3816 times

aBUGSworstnightmare
Posts: 1492
Joined: Tue Jun 30, 2015 1:35 pm

Re: Pixel desktop is not using full screen resolution

Tue Oct 18, 2016 11:18 am

O.K. ... must be something else (and not Pixel related) since old Jessie image shows same result.

So ... I will stop further investigation on this topic (at least for now) and simply use the display as-is @ 1200x760pixel. Image quality of the Nexus 7 display is great (it's IPS technology) and resolution when using 'overlays' (OMXplayer/Kodi) 'switches' to WXGA anyhow, so who cares about some missing pixel at this PPI ratio :shock:

Return to “Advanced users”