Arndale: Ubuntu: HDMI: Can only use hard coded resolution. EDID doesn't work

[Fathi Boudra]

See https://bugs.launchpad.net/arndale/+bug/1078643 for history.

To enable HDMI, we used a work around:

drm_kms_helper.edid_firmware=edid-1920x1080.fw

the parameter will force the resolution. It will work only on monitor that supports this resolution.

For the record, Andy Green's suggestion:
if the problem is failed EDID read, there is a checksum per 128 bytes of EDID, so you will see log info about it.
If it's coming from that direction, check your power arrangements for generating 5V on the HDMI link.
If you're taking the approach to keep it powered down until you check for monitor hpd, be aware monitors may delay hpd assertion from 5V becoming available, for a second or more.
They won't necessarily provide EDID result until after they have signaled back hpd.
If that's related, quick fix is keep the 5V on the HDMI all the time from boot.

[Anmar Oueja (anmar)]

Tushar: Do we care about this for the Ubuntu member build or hard coded resolution is enough?

[Tushar Behera (tusharbehera)]

It would be good to keep this bug open, as we would like to have a logical solution to this. As for Ubuntu builds, this issue is not blocking us. So we can mark this as a low priority bug.

[Milosz Wasilewski (mwasilew)]

Samsung boards are not supported any more.