2008-07-23 01:56:40     LCD image shift

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2008-07-23 01:56:40     LCD image shift

Linux Newbie (INDIA)

Message: 59259   

 

Hi,

 

Our project has LCD display and ethernet. if we do system(ifconfig) in our code, we see some shift in LCD image. Our guess is that on calling system(ifconfig), interrupts were masked, hence there is some line image shift in LCD. Can you please suggest how to overcome this issue.

 

Thanks in Advance

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2008-07-23 02:13:13     Re: LCD image shift

Yi Li (CHINA)

Message: 59260   

 

Please post the system information in detail:

 

What is the processor type. What is the kernel version. The more, the better.

 

Also did you run "video_test" program?

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2008-07-23 03:05:55     Re: LCD image shift

Linux Newbie (INDIA)

Message: 59262   

 

BF533

 

2007R1 distribution.  No we havent run "video_test" program. Ours is customised board and not stamp board

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2008-07-23 03:07:00     Re: LCD image shift

Appalayagari Sreedhar (INDIA)

Message: 59263   

 

Hi,

 

Image shift is due to the Interrupts missing, how many lines you have configured for L1 dma buffer for display.

 

just try increasing the number of lines by doubl, so the number of interrupts per second will reduce this may help u.

 

Best Regards,Sreedhar

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2008-07-23 03:22:15     Re: LCD image shift

Javier Herrero (SPAIN)

Message: 59264   

 

Hi,

 

The problem is probably related to PPI underflows, since the slow external memory accesses can block the DMA enough time to produce an underflow, whose effect is LCD image shift (been there, seen that ) . Check the wiki, http://docs.blackfin.uclinux.org/doku.php?id=ppi , troubleshooting section. Most of the framebuffer drivers does not use interrupts except for error handling.

 

Regards,

 

Javier

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