AM5748: How to enable/disable video out from HDMI port?

Yong Zou

Part Number: AM5748

Hi,

Our project is using AM5748 as main CPU, SDK is based on ti-processor-sdk-linux-am57xx-evm-08_02_01_00. We have built our own custom board and use our own build platform to build u-boot, kernel, file system, it can successfully boot up and display WEB GUI on HDMI port.

We need to implement a power-saving feature on HDMI port which can enable/disable video output from HDMI port, can anyone tell how to do it either from Linux command or an API of library?

Regards,

Yong

over 1 year ago

0 Josue Zamitiz-Ayala over 1 year ago

TI__Mastermind 32295 points

Hello Yong,

Please see the following thread for information:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/968836/am5728-how-to-turn-off-hdmi-output

Regards,

-Josue

0 Yong Zou over 1 year ago in reply to Josue Zamitiz-Ayala

Prodigy 110 points

Hi Josue,

Sorry, that link doesn't give which command or API can be used to enable/disable.

Thanks for help.

Regards,

Yong

0 Josue Zamitiz-Ayala over 1 year ago in reply to Yong Zou

TI__Mastermind 32295 points

Yong,

Please read the documentation for DSS as pointed to by Sunita.

As well as the registers you could write to to disable the displays depending on the display pipeline being used. You could write to the registers using omapconf or preferred method of choice.

I hope that helps.

-Josue

0 Yong Zou over 1 year ago in reply to Josue Zamitiz-Ayala

Prodigy 110 points

Hi Josue,

In SDK ti-processor-sdk-linux-am57xx-evm-08_02_01_00 kernel, there is only one file under drivers/gpu/drm/omapdrm/displays/: panel-dsi-cm.c, which is not for HDMI, so displays module cannot be used.

I also tried omapconf tool to change DSS related registers, following register changes make video output to black-blank on HDMI, but cannot put monitor into power saving mode.

1) DISPC_GFX_ATTRIBUTES (0x580010A0) bit-8 CHANNELOUT --> 0x0

2) DISPC_CONTROL1 (0x58001040) bit-1 TVENABLE --> 0x0

I am looking for function to stop sending any video signal on HDMI interface, so that monitor connected can be in power saving mode.

Regards,

Yong

0 Josue Zamitiz-Ayala over 1 year ago in reply to Yong Zou

TI__Mastermind 32295 points

Yong,

Please allow me sometime more time to look into this query, I will try to get an answer by Wednesday. This is not a feature that is part of our standard offering.

I appreciate your patience.

-Josue

0 Josue Zamitiz-Ayala over 1 year ago in reply to Josue Zamitiz-Ayala

TI__Mastermind 32295 points

Hello Yong,

Due to other priorities, I have not been able to make progress on your query.

Please expect some further delay.

-Josue

0 Josue Zamitiz-Ayala over 1 year ago in reply to Josue Zamitiz-Ayala

TI__Mastermind 32295 points

Hello Yong,
I will follow up offline.

-Josue

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AM5748: How to enable/disable video out from HDMI port?