Nouveau Needs Help Testing Their New Atomic Mode-Setting Support

A few days ago I wrote about Nouveau atomic mode-setting and DP MST patches while now DRM subsystem maintainer Ben Skeggs is soliciting more testing from the open-source NVIDIA community for trying these big changes to the Nouveau KMS driver.

Ben wrote Friday on the Nouveau mailing list, "As the atomic modesetting transition is basically a rewrite of the KMS portion of the driver, I would be very grateful for any additional testing that people could provide (even as simple as just booting and making sure you get a display is valuable)."

If you have some time this weekend or in the week ahead and don't mind building an experimental kernel, fire it up. The Nouveau code continues to be developed on GitHub.

Nouveau's atomic support trails the Intel driver which has good atomic support since Linux 4.9 while is coming out sooner than the AMDGPU code that depends upon DAL and haven't seen any atomic work for the mature Radeon DRM driver. Atomic mode-setting allows setting output modes more cleanly and straight-forward by either being able to succeed or fail in one-go while also being able to test a desired mode in advance of the commit operation, reducing possible flickering situations while being faster.

The DisplayPort Multi-Stream Transport (DP MST) allows for powering multiple monitors off a single DisplayPort connection while is also used by some higher-end displays.

So far the comments from this test request on the mailing list do indicate some regressions, including miniDP to DVI adapters not working. Hopefully the Nouveau atomic support will be ready to go for Linux 4.10.