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  3. AR# 68138: HDMI Receiver Subsystem v2.0 (Rev. 2) - Why is the frame rate incorrectly detected as 15 FPS (Frames Per Second) when the resolution is set to 4K and identified as a custom resolution?

AR# 68138

HDMI Receiver Subsystem v2.0 (Rev. 2) - Why is the frame rate incorrectly detected as 15 FPS (Frames Per Second) when the resolution is set to 4K and identified as a custom resolution?

Description

Why is the frame rate incorrectly detected as 15 FPS (Frames Per Second) when the resolution is set to 4K and identified as a custom resolution?

This can happen if the VIC is set to 0, or to another number that is not in the cross reference. These resolution get identified as [Custom Mode] resolutions.

Solution

This issue affects all resolution that are above 3.2Gbps. This happens because for resolutions above 3.2Gbps, the TMDS clock ration is changed from 10:1 to 40:1, and the calculation for the frame rate for custom resolutions does not take this into account.

As a result the frame rate gets reported as 15 FPS instead of 60 FPS.

This issue will be fixed in the updated driver for the HDMI Receiver Subsystem v2.0 in Vivado 2016.4.

Note: Vivado 2016.3 users should see (Xilinx Answer 68153) for a patch.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
68153 2016.3 - HDMI Receiver Subsystem, Software Driver v3.0 - HDMI Receiver Subsystem Software Driver v3.0 Patch Download N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
67292 HDMI RX Subsystem v2.0 - HDMI RX Subsystem incorrectly detects 1080p 16-bits bpc video source N/A N/A
AR# 68138
Date 11/17/2016
Status Active
Type General Article
IP