Configuring the Raspberry Pi - Raspberry Pi User Guide - page 81

❍ hdmi_mode— In addition to setting the video mode for the analogue composite out-
put, it's also possible to override automatic resolution detection on the HDMI port.
his is handy if you want to run your Pi at a lower resolution than the display's native
resolution in order to make things more readable from a distance. Appendix B, “HDMI
Display Modes”, lists the possible values for this setting.

❍ hdmi_drive —It's also possible to alter the voltage output by the HDMI port. his is
important when you're using an HDMI to DVI adapter, because HDMI and DVI volt-
ages difer slightly. If you ind that your picture is snowy or blown out with too bright
an image, try altering this setting. Possible values are:
• 1 —DVI output voltages. In this mode, no audio is included on the HDMI cable.

• 2 —HDMI output voltages. In this mode, audio is included on the HDMI cable.
❍ hdmi_force_hotplug —Forces the Raspberry Pi to use the HDMI port, even if it
doesn't detect a connected display. A value of 0 allows the Pi to attempt to detect the
display, while a value of 1 forces the Pi to use HDMI regardless.

❍ hdmi_group —Sets the HDMI group mode to CEA or DMT. You should change this
setting according to the display type you're trying to connect, before using hdmi_mode
to control the output resolution and frequency. he two possible values are:
• 1 —Sets the HDMI group to that deined by the Consumer Electronics Association

of America (CEA). Use this setting when the Pi is connected to a high-deinition
television (HDTV) over HDMI and use the irst settings list from Appendix B,
“HDMI Display Modes”.
• 2 —Sets the HDMI group to that deined by the Video Electronics Standards

Association (VESA) in the Display Monitor Timings (DMT) speciication. Use this
setting when the Pi is connected to a computer monitor over DVI and use the
second settings list from Appendix B, “HDMI Display Modes”.

❍ hdmi_safe —Forces the Pi to use a pre-set collection of HDMI settings designed to
provide maximum compatibility with displays connected to the HDMI port. Setting
this to a value of 1 is the equivalent of setting hdmi_force_hotpug=1 , config_
hdmi_boost=4 , hdmi_group=1 , hdmi_mode=1 and disable_overscan=0 .

❍ conig_hdmi_boost —Some monitors require more power on the HDMI output to
operate. If your picture is covered in snow, try increasing this value in stages from 1
(for short cables) to 7 (for long cables).