2011-03-08 01:11:58     Mips for LCD driver uisng Frame Buffer model

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2011-03-08 01:11:58     Mips for LCD driver uisng Frame Buffer model

Appalayagari Sreedhar (INDIA)

Message: 98699   

 

Hi,

 

Can anyone tell me the amount of mips consumed for LCD driver (320 * 240) with the frame buffer model.

 

Thank you.

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2011-03-08 10:15:56     Re: Mips for LCD driver uisng Frame Buffer model

Mike Frysinger (UNITED STATES)

Message: 98728   

 

that question doesnt make much sense.  if you arent writing to the framebuffer, then no mips are taken up because dma is moving the data from the frame buffer to the lcd.

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2011-03-09 02:10:16     Re: Mips for LCD driver uisng Frame Buffer model

Appalayagari Sreedhar (INDIA)

Message: 98747   

 

Dear Mike,

 

We did write the data to the framebuffer from user space which is created using mmap.

 

but we osberve that the lcd browsing is sluggish. so we want to know the reasons which causes the sluggish browsing.

 

So we suspected mips could be the reason.

 

Can you please provide your thoughts on this. how to improve the speed?

 

Thank you, Sreedhar.

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2011-03-09 02:21:24     Re: Mips for LCD driver uisng Frame Buffer model

Mike Frysinger (UNITED STATES)

Message: 98748   

 

sluggish updates usually are not a mips issue.  much more likely to be a system bandwidth issue.

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2011-03-09 02:28:14     Re: Mips for LCD driver uisng Frame Buffer model

Appalayagari Sreedhar (INDIA)

Message: 98749   

 

Hi Mike,

 

Thank you very much for the quick response.

 

How to measure the bandwidth usage, the system runs in ADSP BF527 based custom hw.

 

Thank you, Sreedhar.

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2011-03-09 02:41:07     Re: Mips for LCD driver uisng Frame Buffer model

Mike Frysinger (UNITED STATES)

Message: 98750   

 

i'm not aware of any way of measuring it at runtime.  calculating the LCD load is trivial, as is the theoretical hardware limits.  the rest is Linux traffic when the cache misses (inst/data).  minimize cache misses and memory traffic as much as possible.

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