Mesa 10.4 Might Re-Enable HyperZ For R600g/RadeonSI

The performance of the upcoming Mesa 10.4 might be better out-of-the-box for R600g and RadeonSI Gallium3D driver users if a new patch is accepted to re-enable HyperZ by default.

HyperZ is an important performance-boosting feature that's been available in the open-source AMD Linux drivers for years but tends to often get flipped on/off every once in a while when bugs are reported about HyperZ causing corruption or stability problems by users. Currently in Mesa Git the HyperZ support is disabled by default in the R600g and RadeonSI drivers.

Published in September were some RadeonSI HyperZ improvements and overall for those using the R600_DEBUG=hyperz workaround to enable the support have been reporting success.

Andreas Boll published a new Mesa patch today: enable Hyper-Z on r600g and radeonsi by default. The patch message reads, "This reverts commit 01e637114914453451becc0dc8afe60faff48d84. Since there many Hyper-Z issues have been fixed or worked around. Enable Hyper-Z by default so that we get enough feedback for the upcoming mesa 10.4 release. If you have issues with Hyper-Z try to disable Hyper-Z using the enviroment variable R600_DEBUG=nohyperz and please report the issue on the bugtracker."

Mesa 10.4 is expected for release in early December.