Investigate compatibility issue with some HDMI devices

[mithro]

See the compatibility update in https://hdmi2usb.tv/crowdsupply/opsis/numato/2016/03/16/crowdsupply-updates-for-2016/

Compatibility Update

During recording LCA, we did discover a compatibility between the Opsis board
and some devices. We are currently investigating the root cause of these
issues and believe it should be resolvable with a firmware update. As a
temporary workaround, you can use HDMI cables which include inbuilt
amplifiers (such as these with Redmere technology from
Monoprice) on the
inputs. A further backer update will be released within 30 days with more
information.

(A bunch of firmware issues were also discovered but are unrelated to this hardware.)

Problem appears a high Word Error Rate (WER) on the channel. You need the latest firmware plus to turn debugging for the input on.

debug input0

Output looks something like

Put something here....

• Random testing spreadsheet
• Random testing results
• Magic Cable testing spreadsheet

Things needing investigation

• 1280x720 @ 50Hz verse 1280x720 @ 60Hz -- 50Hz input only works on some laptops (some laptops seem to only do 60Hz?)
• Input1 not working on Opsis board in the speaker's room
• Is there a difference between the "preproduction" and "production" boards
  • Investigate the 3V3 power rail. It changed between the two runs.
• Check if problem can be resolved in firmware.