display mirror Linux 3.10.53

display mirror Linux 3.10.53

[carlos.casillas]

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Hello all,

Some customers are asking for how to mirror the LCD screen (LVDS) on a HDMI display.
I have reached and I found many references about enabling a secondary frame buffer and then a echo and dd on it; however, the secondary screen is corrupted (has a different resolution). When using two LVDS screens, the secondary screen is shown properly, but just the frame shown when the dd command was called is printed.

Does anyone know how to dynamically "clone" the primary screen (LVDS) on a HDMI display (either on boot time or user space)?

Thanks in advance!
/Carlos

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Re: display mirror Linux 3.10.53

[Nikolay Dimitrov]

Hi Carlos,

On 02/13/2015 03:05 AM, carlos.casillas@freescale.com wrote:
> Hello all,
>
> Some customers are asking for how to mirror the LCD screen (LVDS) on a
> HDMI display.
>
> I have reached and I found many references about enabling a secondary
> frame buffer and then a echo and dd on it; however, the secondary screen
> is corrupted (has a different resolution). When using two LVDS screens,
> the secondary screen is shown properly, but just the frame shown when
> the dd command was called is printed.
>
> Does anyone know how to dynamically “clone” the primary screen (LVDS) on
> a HDMI display (either on boot time or user space)?

Xorg supports display cloning, but copying graphics data to the cloned 
display will consume some bus bandwidth even if DMA is used. This can 
add significant load to designs using low-budget memory subsystems.

Also, I'm not sure whether the VPU-accelerated video playback will be 
handled across the cloned displays :(.

Regards,
Nikolay