RadeonHD Driver Delivers AMD 780 Support

In early March AMD had announced the 780 Series Chipset for motherboards, which is designed to be the low-end Phenom-compatible version of the 790FX Chipset. What makes the 780G and 780V Chipsets special, however, are their integrated Radeon HD 3200 graphics. In March we had delivered our Linux review of the Radeon HD 3200 and were pleased by the results for this IGP that had performed at about the same rate as the discrete Radeon HD 2400PRO. The Radeon HD 3200 also possesses a Unified Video Decoder (UVD) and Hybrid CrossFire for splitting the graphics rendering load in a similar fashion to CrossFire but between the 780G and a compatible PCI Express x16 graphics card. Neither of these two features, however, are supported by any Linux driver -- right now.

The AMD 780 Series Chipsets have been available for nearly four months now, and supporting the Radeon HD 3200 graphics since day one has been AMD's proprietary Catalyst driver. On the open-source side, there has been the Radeon HD 3200 / 780G support quite quickly through the xf86-video-ati driver due to its use of AtomBIOS, but the support within the RadeonHD driver hadn't arrived until earlier today. Thanks to 22 code commits made to the mainline xf86-video-radeonhd git tree, it's now possible to use this newest AMD integrated graphics processor with this Novell-spawned driver.

In delivering this support, the RadeonHD driver now depends upon AtomBIOS for supporting PCI-E connectors with their connection type being defined in one of the AtomBIOS tables as well as the PCI Express lanes. Much larger, however, is the PCIEPHY transmitter being handled by the RadeonHD driver through AtomBIOS. The RadeonHD driver started using AtomBIOS for transmitter support with the Uniphy for the Radeon HD 3400/3600 series (Radeon HD 3650 Linux review). This was done due to the lack of documentation at the time that AMD had released to the Novell developers covering the Uniphy transmitter. These developers have since received the register documentation for the Uniphy transmitter, but the RadeonHD driver is continuing to use AtomBIOS due to the lack of development time to rewrite this support. With the PCIEPHY for the AMD 780 Chipsets, they were in a similar boat of lacking documentation for this transmitter so they have employed AtomBIOS here too.

In the code commits today is also other needed work such as adding callback support to MC, support for LVDS for the LVTMA transmitter, and adding the RS780 IDs to Conntest, the RadeonHD connector utility.

We had tested out the latest xf86-video-radeonhd git code as of this afternoon and had experienced success with the ECS A780GM-A v1.0 motherboard. The Radeon HD 3200 / AMD 780 support in the RadeonHD driver covers DVI/HDMI/LVDS and DAC outputs. DisplayPort support in the open-source drivers are still being worked on for the 780 Chipsets and all other Radeon/FireGL GPUs for that matter. The specific RS780 PCI IDs that are supported by xf86-video-radeonhd are 0x9610, 0x9611, 0x9612, 0x9613, and 0x9614. Share your experiences with the ATI Linux drivers in the Phoronix Forums.

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