X.Org Server 1.18.3 Has A DRI3/Present Fix To Avoid Eating Your CPU & Other Issues
There still isn't any word on making the X.Org Server 1.19 release but xorg-server 1.18.3 was tagged this afternoon with a few fixes, including an important fix for DRI3's Present extension.
There's a performance fix in X.Org Server 1.18.3 to avoid having DRI3 fully consume a CPU core, also attributed to the same faulty commit with the X.Org Server on the Intel driver causing memory to be leaked at 600 MB/s, and apparently it caused a Steam hang when using Radeon graphics with DRI3. This is the one-liner fix with the bit of the technical explanation.
It's great to see DRI3 getting further fixed up as it can greatly improve performance but the popular Linux graphics drivers have it currently disabled by default due to various issues affecting some users. With this latest fix over "present: Only requeue for next MSC after flip failure", hopefully more of the remaining problems are wiped out.
X.Org Server 1.18.3 also has some XWayland and GLAMOR fixes, the AMD Polaris PCI IDs for the DRI2 code, and other alterations. More details via the mailing list release announcement.