Dual displays, one chipset

[nelsonn]

I'm interested in displaying two independent screens of data on two LCDmonitors using one 855-equipped CPU board. The LVDS, though dual channel, seems to be limitted to one processing pipe, so I'm assuming it can't be used this way.I can't tell whether the DVO channels have this limitation. One DVO channel is sufficient for each screen (fairly low res) so I'm wondering how the dual DVO ports can be used for this end. Can I render two separate frame buffers (actually four since therewill bea front and back for each screen) and tell the 855 to send one on the first DVO channel and the other on the second channel, with the output connector split appropriately to drive two monitors? The manual refers to "concurrent display" for this but offers no further info. Thanks for any insightanyone can give me.

Nick

[Chuck_De_Sylva]

From a software application point of view, the two pipes of the Intel 82855GM Graphics Controller are exposed to the system simple as two separate controllers (just like inserting two PCI controllers into a desktop system).

You can render two separate frame buffers, just like you would if you had two physical discrete adapters.

However, as you say, the LVDS (local flat panel) is limited to one of those controllers. The other controller would have its output based on whatever DVO solution your motherboard has. (i.e. external DVI Flat Panel, TV-Out, etc.)

[nelsonn]

Thanks for replying so quickly, Chuck. I'm a little confused about the table of display pipes in 6.4.5.1 of the 855GMCH manual. It suggests to me that when pipe A is used forone of the outputsin its column, pipe B can only be used for the corresponding output in its column. For example, if A is used for aCRT, B can only be used for the internal LVDS or the DVO (single or dual channel).And there is no row with DVO B in one column with DVO C in the other.If I wanted to drive two identical LCDs using the same software (an OpenGL subsetwith a self-writtenhardware driver) would it be possible to output one frame buffer using DVO B and the other using DVO C? If so are there any publications or guides that address this?

I am asking for an embedded application in which the main processing will be done in one box and the two displays will be separately mounted. The OS is home-made, and very simple. These displays will be 1024x768 at 60 Hz, so a single DVO channel is sufficient to drive each. The displaysare identical,and must be hardware-interchangeable (driven in the same manner, such that they may be swapped at their cable ends with no other modifications to the system).

I have minimal experience with driving displays, so maybe I'm off-base in thinking using the LVDS for one display and the DVO for the other would mean that they would have to be handled differently on a software and/or hardware level.

Nick

[wayn01]

Hi Nick

I have a similar problem.

I want to drive 2 x LVDS large 19" displays direct from an Intel graphics chipset but do not know if there is an Intelchipset to support my requirements.

The 19" LVDS displays are 48 bit and need 2 channel LVDS to support this.

Can the DVO support 48 bitor 24 bit LVDSor would I need 2 DVO to support this requirement?

Is there an Intel graphics card with this highgraphics performance?

Wayno