underflow interrupt occur in eLCDIF in i.MX7D

[ko-hey]

Hi all

I have questions about eLCDIF in i.MX7D.

When MIPI-DSI image distortion occurred, I found the that underflow interrupt occurred in eLCDIF.

UNDERFLOW_IRQ bit of LCDIFx_CTRL1n is set after image distortion has occurred.

I want to resolve this underflow interrupt and have following question.

Q1.

I found the following description in p3636 of RM.
"Underflow interrupt is asserted when the clock domain crossing FIFO (TXFIFO) becomes empty but the block is in active display portion during that time. Software should take corrective action to make sure that this does not happen."

Could you tell me the "corrective action" concretely ?

Q2.

I expected that it is a function which is prepared as a remedy measure when an underflow interrupt occurs, but image disorder was not resolved even if the bit was set.

Please describe the function details of RECOVER_ON_UNDERFLOW of LCDIFx_CTRL1n.

Q3.

I found following thread which is for i.MX50.

i.MX50 eLCDIF RECOVER_ON UNDERFLOW 

Is it same as i.MX7D ?

Ko-hey

[Yuri · Accepted solution]

Hello,

1.

  The "corrective action" means any activity to provide data to the TXFIFO in time. Really this is application

depended issue. Often system performance is not enough to keep proper throughput for all data flows.

Therefore please analyze system activities and tasks, that consume (CPU, memory) resources.

2.

  The Recover bit serves just for operations continuation, it cannot improve display image.

3.

  Yes, the LCDIF IP of i.MX50 is very similar to i.MX76 one.

Have a great day,
Yuri

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