Features/DisplayPort

DisplayPort support

Summary

Enhanced support for DisplayPort in X and kernel drivers.

Owner

• Name: Adam Jackson
• email: ajax@redhat.com

Current status

• Targeted release: Fedora 12
• Last updated: 2009-06-24
• Percentage of completion: 10%

Detailed Description

DisplayPort is a new digital display connector and protocol. While much more capable than DVI, it's also much more complicated, and some work is needed to take advantage of it.

Benefit to Fedora

DisplayPort has a higher link bandwidth than dual-link DVI. Monitors can take advantage of this by providing higher resolutions, higher color depths, and higher refresh rates. DisplayPort also runs at a lower voltage than DVI and LVDS, using less power. Future laptops will likely switch to embedded DisplayPort for the local panel for this reason. With this feature, Fedora users can take advantage of the the technical superiority of DisplayPort.

Scope

Every device with a DisplayPort PHY will almost certainly need driver work to enable it. At the moment this includes the big three of intel, radeon, and nouveau. Some DisplayPort functionality will likely be common among all devices and can be lifted to helper routines in the X server or drm core.

Affected packages:

• kernel
• xorg-x11-server
• xorg-x11-drv-{ati,intel,nouveau}

How To Test

See this grid? Fill it in.

Device	DisplayPort sink	DP-to-HDMI converter	DP-to-DVI converter	DP-to-VGA converter	Embedded DP
ATI Radeon, UNIPHY (>=RV630)	?	?	?	?	?
ATI Radeon, DVO (<RV630)	?	?	?	?	?
Intel GM45	?	?	?	?	?
NVIDIA	?	?	?	?	?

For full rigor points, make another set of grids per device class, with DP/HDMI/DVI/VGA as both rows and columns, and test hotplug switching between all cases.

Known DP sinks:

• Apple: 24" LED
• Dell: 2408WFP, 3008WFP
• HP: LP2275w, LP2480zx

Known DP sources:

• ATI UNIPHY: FirePro V8700 (probably), RadeonHD 3650
• ATI DVO: FireGL V7700, FireMV 2260 (probably)
• Intel: Various motherboards and laptops, FIXME give examples
• NVIDIA: Quadro NVS295, Quadro NVS540, Quadro FX580

User Experience

DisplayPort connections should Just Work.

Dependencies

DisplayPort sinks with EDID are required to support EDID 1.4. This is landed.

eDP sinks may use DisplayID instead. This is kind of written, but we don't have any eDP devices to test with yet, so who knows.

Possible common functionality: link/lane computation, manual link training, dongle identification, various other AUXCH services.

Some IHV communication may be necessary to get details on specific DP PHYs.

Contingency Plan

None necessary. It doesn't work in F11, so it can continue to not work in F12.

Documentation

Ideally, none needed, besides "DisplayPort just works now". It's not like we have documentation for DVI. However, if the support matrix above doesn't get completely filled in, then we will probably want to mention exactly which chips have DP support.

Release Notes

DisplayPort is likely to require kernel support in a much stronger way than DVI, since hotplugging the monitor requires another link training cycle, and the only reliable way to detect that is with interrupts. UMS configurations may accidentally work in some situations, but this is not recommended.

Comments and Discussion

• See Talk:Features/DisplayPort