AMD Makes Open-Source "Iceland" GPU Support Experimental In Linux 4.3

AMD sent in a batch of fixes for the AMDGPU kernel driver today for Linux 4.3. One notable change with this AMDGPU DRM driver update is that it marks the Iceland/Topaz graphics processor support as experimental so it's no longer enabled by default until the support has been better vetted.

Resulting from this bug report about a Radeon R7 M260/M265 mobile graphics processor having unusable rendering support by the open-source driver and not working correctly, all Iceland GPU support provided by the AMDGPU driver is now marked as experimental.

While the hardware enablement code is there, Alex Deucher commented that "we haven't really tested [the Topaz GPUs] much" so it's better to just mark the support as experimental until AMD's open-source staff finds the time to fix the problems. The affected PCI IDs are 0x6900, 0x6901, 0x6902, 0x6903, and 0x6907 for the Topaz/Iceland GPUs that are now marked as experimental.

If you have a Topaz GPU in your system and want to attempt to use the AMDGPU support anyways on Linux 4.3, the amdgpu.exp_hw_support=1 module parameter needs to be used to override the experimental support flag. This shouldn't be too much of a big deal since the Topaz GPU is just used by a limited number of mobile Radeon graphics laptops.

The other fixes in today's AMDGPU pull request can be found here.