FAQ: [#6592] PPI hardware/driver often capture corrupt images from image chip(2011)

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[#6592] PPI hardware/driver often capture corrupt images from image chip

Submitted By: Marius Kotsbak

Open Date

2011-05-11 05:30:27    

Priority:

Medium     Assignee:

Scott Jiang

Status:

Open     Fixed In Release:

N/A

Found In Release:

2011R1     Release:

Trunk (ec45f5f)

Category:

Drivers     Board:

Bluetechnix CM

Processor:

BF537     Silicon Revision:

Is this bug repeatable?:

Yes     Resolution:

Assigned (Not Start)

Uboot version or rev.:

    Toolchain version or rev.:

09r1-11

App binary format:

N/A     

Summary: PPI hardware/driver often capture corrupt images from image chip

Details:

 

Often the images captured by the bfin_ppi linux module are corrupted, even if no error (under/overflow) is detected/reported. It seems like some pixels are moved to the previous line.

 

See the attached image for an example. Note the errors on the right side. The image is supposed to be light in the one quarter in the top left and darker in the rest of it. Clearly the stripe on the right is pixels from the left part.

 

I am not certain if this is caused by driver error, processor error or something else.

 

Follow-ups

 

--- Marius Kotsbak                                           2011-05-11 05:48:13

The image chip is a Micron MT9P031 and the settings used are:

 

  { CMD_PPI_SKIPPING, CFG_PPI_SKIP_DISABLE },

  { CMD_PPI_DATALEN,  CFG_PPI_DATALEN_8 },

  { CMD_PPI_PACKING,  CFG_PPI_PACK_ENABLE },

  { CMD_PPI_CLK_EDGE, CFG_PPI_CLK_EDGE_FALL },

  { CMD_PPI_TRIG_EDGE, CFG_PPI_TRIG_EDGE_RISE },

  { CMD_PPI_XFR_TYPE, CFG_PPI_XFR_TYPE_NON646 },

  { CMD_PPI_PORT_CFG, CFG_PPI_PORT_CFG_XSYNC23 },

  { CMD_PPI_SET_DIMS, CFG_PPI_DIMS_2D },

  { CMD_PPI_DELAY, 0 },

  { CMD_PPI_LINELEN, 2592 }

  { CMD_PPI_NUMLINES, 1944 }

 

--- Mike Frysinger                                           2011-05-11 13:21:35

didnt you already file this as [#6543] ?

 

--- Marius Kotsbak                                           2011-05-11 15:01:37

No, that is a similar bug, but not exactly the same symptoms, and that is for

EPPI in BF548 and this one PPI in BF537.

 

--- Scott Jiang                                              2011-10-21 03:28:39

It may caused by timing mismatch in hardware or software. The resolution seems

strange, you may use oscilloscope to monitor real timing.

 

--- Marius Kotsbak                                           2011-10-21 05:58:11

Yes, we have monitored this with oscilloscope too without finding any errors in

the signals. But now we have given up the whole platform and moved over to ARM

from TI as Analog Devices does not seem to be interested in solving neither the

problems with EPPI or PPI. There we don't have any reading problems with the

same image chip hardware and working Linux drivers are available.

 

 

 

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File Name     File Type     File Size     Posted By

2011-05-03_13-48-52.bmp    image/bmp    5039926    Marius Kotsbak

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