Baytrail dual display capabilities

[CAstu]

Hi,

I have a system with Baytrail processors (E3480, E3823, E3822, and others) that disables the LVDS when display port is connected during boot up. I have been trying to look on the internet if that is a dual display combination that should work or not. Does anyone know if this should work and where I can find this information for future reference?

Regards

[EstebanA_C_Intel]

Hello, CA01:

Thank you for contacting the Intel® Communities.

I would like to know if you are able to select a default output device for the display at BIOS level.

If this is positive, what are the options to select there?

I look forward to hearing from you.

Regards,

Esteban C

[CAstu]

Hi Esteban,

The BIOS just allows me to select between internal graphics or PCIE. But my question is more related to the VBIOS capabilities, i.e. whether the VBIOS, if configured properly, would be able to show the image on the LVDS and DP at the same time.

I know the VBIOS can be modified to boot from the LVDS when both DP and LVDS are connected, but I need to know if there is a processor limitation to accomplish dual display when using these two interfaces. So far I have measured the LVDS signals and the whole LVDS port is disabled when connecting something to the DP.

Regards

[EstebanA_C_Intel]

Hello:

Is this only while you are at the BIOS?

Do you have the option to manually select a "primary" display in BIOS?

At BIOS, the dual display is not available since all the drivers are loaded until the system boots to the OS.

Please let us know if this the scenario in your system.

Regards,

Esteban C

[CAstu]

Hi Esteban,

Yes, this is only at boot-up, inside the operating system works fine. Also, in the BIOS I can only select between internal graphics or PCIE, as mentioned before

On the other hand, I understand all drivers are loaded until the operating system boots, but that is why I would like information about the VBIOS capabilities. I know the VBIOS is capable of dual display but is limited to some configurations, i.e. CRT+DP work but CRT+HDMI will not.

Could you please let me know what dual display configurations can be accomplished by the VBIOS? Or at least let me know if LVDS+DP would work?

We actually have the possibility to change the VBIOS and create a new BIOS version, but before I get in touch with the BIOS team, I would like to find out first what options we have.

Regards,

Carlos

[EstebanA_C_Intel]

Hello, CA01:

I would like you to check this article related to enabling dual display in DOS or VBIOS.

http://www.intel.my/content/dam/www/public/us/en/documents/application-notes/dual-displays-during-startup-appl-note.pdf http://www.intel.my/content/dam/www/public/us/en/documents/application-notes/dual-displays-during-startup-appl-note.pdf

I look forward to your feedback on this.

Regards,

Esteban C

[CAstu]

Hi Esteban,

I understand the difference between the VESA and VGA modes, but the document doesn't answer my question directly. I know Intel sometimes has documentation with tables showing what interfaces should work with dual display in VBIOS, which is based on what data can be sent to two displays on the same pipe.

Since the VBIOS comes from the Graphics team, normally they use VGA modes and I am not sure about EMGD. I also know that EMGD and normal VBIOS are different.

But still, I don't think my question is completely understood. I don't need help to enable dual display in the VBIOS, what I need to know is if there is a limitation from the VBIOS to enable dual display between LVDS and DP, as they would be using the same pipe.

Regards,

Carlos

[EstebanA_C_Intel]

Hello, CA01:

I found the information below in the link shared previously.

Page 4 http://www.intel.my/content/dam/www/public/us/en/documents/application-notes/dual-displays-during-startup-appl-note.pdf?_ga=1.36305127.693180906.1435769197&elq_cid=1360440 http://www.intel.my/content/dam/www/public/us/en/documents/application-notes/dual-displays-during-startup-appl-note.pdf?…

: " Pipe Limitations

Many of the built-in display ports on Intel chipsets available now (such as LVDS, eDP,

etc.) have a restriction, by design, that does not allow them to share their pipe with

another port. Thus, by definition, you cannot Twin them, and must Clone them which

tends to be what is needed anyway."

I hope this clarifies your inquiry.

If more information or support is required, feel free to contact us back.

Regards,

Esteban C

[CAstu]

Hi Esteban,

I did read the document and I understand I cannot twin the displays. However, it says I can clone the displays, but I seriously doubt every dual display combination will work as long as I use clone mode, since the data going through the pipe changes according to the EDID used.

Since we have been going around in circles with this question, I would just ask a yes/no question:

- Is the VBIOS capable of cloning LVDS+DP on Baytrail?

I am not trying to be rude but I was expecting a more direct answer.

Regards,

Carlos

[EstebanA_C_Intel]

Hello, CA01:

In order to get a dual display at BIOS level, you would have to modify the BIOS (this will be done by OEM) to enable the clone feature in it.

My recommendation would be to check with the manufacturer of your device to check if this can be done.

With a regular system, dual display at BIOS is not enable.

Regards,

Esteban C