How to add a HDMI resolution to the sunxi kernel

To add resolution to sunxi kernel:

1. Get a Debian VM

2. Install toolchain: 
    # apt-get curl git
    # echo "deb http://emdebian.org/tools/debian/ jessie" main > /etc/apt/sources.list.d/crosstools.list
    # curl http://emdebian.org/tools/debian/emdebian-toolchain-archive.key | sudo apt-key add -
    # dpkg --add-architecture armhf
    # apt-get update
    # apt-get install crossbuild-essential-armhf
    
3. Get the Cubian source
    # git clone https://github.com/mmplayer/linux-sunxi.git -b dev/sunxi-3.4 --depth=1
    
4. Move into drivers/video/sunxi/

5. Edit hdmi/hdmi_core.h
    Add new mode after "#define HDMI1280_1024_60(HDMI_NON_CEA861D_START + 1)"
		For example, "#define HDMI1680_1050_60(HDMI_NON_CEA861D_START + 2)"

6. Edit hdmi/hdmi_core.c:
    Add timings before "{ HDMI_EDID, }" line, for example
			"{ HDMI1680_1050_60,   146000000,  0,  1680, 1050, 2240, 456, 104,176, 1089, 36,  3,  6, 0,  0,  1 },"
    To calculate the values, I used http://www.epanorama.net/faq/vga2rgb/calc.html
    The values are in the order 
      VIC	Video configuration ID (I'm not sure what VIC stands for, but it's clearly just the identifier)
      PCLK	Pixel clock frequency (in Hz)
      AVI_PR	Not sure what this means, it seems to be enabled only on interlaced resolutions
      INPUTX	The pixel width of the display
      INPUTY	The pixel height of the display
      HT	The horizontal total (note: this is INPUTX + HBP + HFP, usually the sync size is also counted, but not here)
      HBP	The horizontal back porch
      HFP	The horizontal front porch
      HPSW	The horizontal sync width (usually it's abbreviated to HSW, I'm unsure why the P is there)
      VT	The vertical total (note: this is INPUTY + VBP + VFP, usually the sync size is also counted, but not here)
      VBP	The vertical back porch
      VFP	The vertical front porch
      VPSW	The vertical sync height
      I		Whether to use interlacing
      HSYNC	The horizontal sync polarity (1 for positive, 0 for negative)
      VSYNC	The vertical sync polarity (1 for positive, 0 for negative)
	
7. Edit hdmi/drv_hdmi.c:
	Add your mode with number to switch after "return HDMI1280_1024_60;"
	  case DISP_TV_MOD_H1680_V1050_60HZ:
	    return HDMI1680_1050_60;

8. Edit disp/disp_lcd.c
    	Add your mode to tv_mode_to_width
	  case DISP_TV_MOD_H1680_V1050_60HZ:
	    width=1680;
	    break;

	Add your mode to tv_mode_to_height
	  case DISP_TV_MOD_H1680_V1050_60HZ:
	    height = 1050;
	    break;

9. Edit ../../../include/video/sunxi_disp_ioctl.h
	Increase DISP_TV_MODE_NUM by 1
	Add your mode (value should be the old value of DISP_TV_MODE_NUM):
	  DISP_TV_MOD_H1680_V1050_60HZ = 0x1c,
	  DISP_TV_MODE_NUM = 0x1d
	This is the value you should use in your fex, but in decimal form (so 0x1c would be 28 in fex)
    
10. Rebuild the kernel without the modules
	# make -j4 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage
    
    
Partial source for these instructions: https://github.com/hglm/a10disp/blob/master/a10disp.c

Can you help me please with adding 1280x800 resolution to this driver?

Can you help me please with adding 1280x800 resolution to this driver?

Not really, I’m afraid. I haven’t done much with sunxi devices since I created this gist. I have no idea what changed over the last 6 years.