intel ivybridge integrated graphics - how to set mode

[mateuszb]

Hi,

I'm trying to figure out on the conceptual level, what are the necessary steps to configure a display mode (resolution) on IvyBridge integrated graphics card? I've downloaded all of the documents at https://01.org/linuxgraphics/documentat ... sor-family but having no luck finding references to "resolution" in any of documents (except a few useless cases).

I understand the basics of how these graphics cards work (command streaming, etc.) but not sure how the display mode is configured? I'm guessing that just sending a 2d surface to a blitter engine with (x, y) dimensions will not automatically update the display mode.

Did anyone try playing with these cards and has any hints?

Also, by any chance, does anyone know what a surface pitch is?

Thanks!

[mateuszb]

For anyone following this and interested in graphics programming on ivy bridge the answer is contained in "Intel® OpenSource HD Graphics Programmer’s Reference Manual (PRM) Volume 3 Part 3: North Display Engine Registers
(Ivy Bridge)"

The general flow is as described in "Display Mode Set Sequence" chapter except it is very obscure.

Proper sequence is described in intelfbhw.c in linux 3.8.3. The steps are described in intelfbhw_mode_to_hw() which configures a structure in host memory. That structure contains registers that will be written by intelfbhw_program_mode() function.

The reason there is no "resolution" keyword mentioned is mostly because the north display engine deals with analog signals on display ports so it seems that the terminology is a bit different than what software folks call it. The registers that configure resolution are Vertical Active and Horizontal Active signals.

[Combuster]

For those reading: Video_Signals_And_Timing covers most of the analog matters, including the typical terminology.

[mateuszb]

That's a very useful link you just posted!

[matute81]

Thank you very much for the information!
I'm not sure if the procedure is the same for all the intel graphics...