displayframebufferxrandredid

convert HDMI timings modline to fbset


I have the following custom timing, I would like to convert it to fbset. There are two parameters which I cannot find horizontal sync length (in pixels and vertical sync length (in pixel lines):

# hdmi_timings=<h_active_pixels> <h_sync_polarity <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

I figured this values from parsing edid file:

hdmi_timings=2560 0 48 32 80 1600 0 3 6 14 0 0 0 30 0 132000000 5

Thank you


Solution

  • I used the following video timing calculator to do the conversion:

    http://www.epanorama.net/faq/vga2rgb/calc.html

    Please consult the following page to understand how front/back porch and margins are correlated. Also, you need to know about the total horizontal and vertical equations to be able to retrieve the Horizontal sync length and vertical sync length.

    http://www.ibiblio.org/gferg/ldp/man/man5/fb.modes.5.html