On Mon, Jun 17, 2013 at 12:07 PM, Adam Jackson ajax@redhat.com wrote:
On Mon, 2013-06-17 at 11:04 -0400, Alex Deucher wrote:
On Mon, Jun 17, 2013 at 10:06 AM, Adam Jackson ajax@redhat.com wrote:
At least on an IBM Power 720, this check passes, but several piglit tests will reliably trigger GPU resets due to the ring buffer pointers not being updated. There's probably a better way to limit this to just affected machines though.
What radeon chips are you seeing this on? wb is more or less required on r6xx and newer and I'm not sure those generations will even work properly without writeback enabled these days. We force it to always be enabled on APUs and NI and newer asics. With KMS, wb encompasses more than just rptr writeback; it covers pretty much everything involving the GPU writing any status information to memory.
FirePro 2270, at least. Booting with no_wb=1, piglit runs to completion with no GPU resets or IB submission failures. Booting without no_wb, the following piglits go from pass to fail, all complaining that the kernel rejected CS:
Weird. I wonder if there is an issue with cache snoops on PPC. We currently use the gart in cached mode (GPU snoops CPU cache) with cached pages. I wonder if we need to use uncached pages on PPC.
Alex