Intel Haswell May Soon See Less Hangs With Mesa
Intel developer Jason Ekstrand published a patch series today where he's trying to "stop hanging on Haswell". He explained, "As I've been working on converting more things in the GL driver over to blorp, I've been highly annoyed by all of the hangs on Haswell. About one in 3-5 Jenkins runs would hang somewhere. After looking at about a half-dozen error states, I noticed that all of the hangs seemed to be on fast-clear operations (clear or resolve) that happen at the start of a batch, right after STATE_BASE_ADDRESS."
The end result is after these seven patches, hangs on Haswell are no longer existent or at least very rare: "I'm not 100% convinced of this explanation because it seems a bit fishy that a context switch wouldn't be enough to fully flush out the GPU. However, what I do know is that, without these patches I get a hang in one out of three to five Jenkins runs on my wip/i965-blorp-ds branch. With the patches (or an older variant that did the same thing), I have done almost 20 Jenkins runs and have yet to see a hang. I'd call that success."
More details via this patch series.