AM625: Support 2 *1080P60 display with same content

Hello ,

Thank you for the query.

Can you please explain your use case in detail

Regards

Rajashri

2 *1080P60 display with same content.

Hello Tony, 

Thank you for the inputs. I captured the key DSS specs and supported features below 

Datasheet Specs 

Below is the Display subsystem capabilities 
– Dual display support
– 1920x1080 @ 60fps for each display

TRM supported features 

DSS integrates two single-link Open LVDS Display Interface transmitters (OLDITX) with the following main features:

• One single-link OLDI output link mode.

• Two single-link (duplicate) OLDI output link mode.

• One dual-link OLDI output link mode.

• 18-bit or 24-bit output with OLDI mapping modes (three or four LVDS data channels, one clock channel) per instance.

• LVDS signaling: Compliant with ANSI/TIA/EIA644-A standard (Electrical Characteristics of Low Voltage Differential Signaling (LVDS) Interface Circuits).

• LVDS transmit throughput performance: WUXGA (1920x1200@60), 162 MHz pixel clock resolution (single link).

• Test support features: Built-in pattern generator; loopback mode.

Figure 12-2292. DSS Environment

Based on the Specifications, supported features and the DSS environment block diagram above, i would tend to think that  it should be feasible to configure the DSS  to display same content. 

I am not sure if there a clone mode that can be set. I do see duplicate mode in the below section of the TRM 

Table 12-4982. DSS_OLDI_CFG Register Field Descriptions : DUPLICATE | Duplicate mode selected -synchronized operation . 

I am not sure if this configuration has been tested,  or if there is any plan to test to confirm this would work.

Below are a few thread indicating the OLDI driver status

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1128751/am625-oldi-driver-or-dts-example/4196166?tisearch=e2e-sitesearch&keymatch=am625%252520LCD%252520krunal#4196166

(+) AM625: Dual-link OLDI output link mode - Processors forum - Processors - TI E2E support forums

Let me know if you have any thoughts.

Regards,

Sreenivasa

Hello Tony, 

Please refer below for the OLDI driver status.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1130687/sk-am62-lvds-oldi-interface-instead-of-hdmi-dss/4197830#4197830

Regards,

Sreenivasa

Sreenivasa,

Clone between two lane within OLDI port 1 is verified on a 3rd party board. which can only be 720P with signal lane in clone mode.

So in order to support dual 1080P60, need to consider clone between two ports.

Hello Tony, 

Thank you for the inputs and understand.

So in order to support dual 1080P60, need to consider clone between two ports.

Is this some thing that has been verified with the third party board ?

Regards,

Sreenivasa

No, they are different customer. 

Hello Tony, 

Thank you.

Let me reframe you question - would it be possible to clone the video port1 and video port 2  to display same content with x1080P60fps.

Pls let me know if my understanding is correct.

Regards,

Sreenivasa

Correct.

I ask it because limited DDR bandwidth can't support dual 1080P60fps if both fetch data from DDR.

Hello Tony, 

Thank you for the inputs.

The supported features includes these capabilities. Below is a thread where we are discussing about enabling the 2 video ports and the current driver status.

(+) SK-AM62: LVDS(OLDI) interface instead of HDMI(DSS) - Processors forum - Processors - TI E2E support forums.

I will reassign the thread to the display expert to provide summary of the implementation and check would it be possible to clone the video port1 and video port 2  to display same content with x1080P60fps.

Regards,

Sreenivasa

Krunal,

There is no single lane OLDI panel support 1080P60 from market. That is the case of AM65x when we promoted to customer who need dual 1080P60. 

So clone within dual OLDI lane is not acceptable although it is OK from SOC side.

Is it possible to clone between port 1 and port 2 within DSS?

Hi Tony,

Currently, we have HDMI and LVDS running concurrently on the SK EVM. We are noticing that both screen are duplicated so I don't see any reason why Port 1 and Port 2 can't be duplicated. 

Regards,
Krunal

Krunal,

Do you mean current driver supports duplicate port 1 and port2 inside DSS? DSS only fetch once for two ports? the DDR loading for dual display is single 1080P60 data?

Hi Tony,

Yes, it seems like the driver is only fetching one buffer and redirecting it to both ports. I am supposed to get a dual display setup in the next few days and will be able to verify the DDR loading aspect. 

Regards,
Krunal