Intel Drops Mode-Setting Rework Patch Bomb

Daniel Vetter of Intel published a massive "patch bomb" of 43 patches to the Intel open-source Linux graphics driver development list as they prepare to re-work mode-setting within their DRM/KMS driver.

These 43 patches, while large in size, isn't the full workload. The 43 patches are just "part one" as the developers do the prep work for the actual mode-setting changes. "The goal of this little adventure is to move away from the crtc helper code, which has the fundamental assumption that encoders and crtc can be enabled/disabled in any order, as long as we take care of depencies. Our hw works differently. We already have tons of ugly cases where crtc code enable encoder hw (or encoder->mode_set enables stuff that should only be enabled in enocder->commit) to work around these issues. But on the disable side we can't pull off similar tricks - there we actually need to rework the modeset sequence that controls all this."

As some of this work there is a rework of the DPMS (Display Power Management Signalling) code, infrastructure for reading the current hardware state, various clean-ups, etc.

The work right now is only lightly tested with more test coverage of TV-Out and DVO encoders needed. Daniel Vetter hopes to submit the actual mode-setting change patches within the next few days as he seeks comment.

For those interested in the changes on the technical side to Intel's Linux DRM driver, see this mailing list thread.