2018-04-12 0:20 GMT+02:00 Gabriel C nix.or.die@gmail.com:
2018-04-11 20:35 GMT+02:00 Jean-Marc Valin jmvalin@mozilla.com:
On 04/11/2018 05:37 AM, Christian König wrote:
With your patches my EPYC box is unusable with 4.15++ kernels. The whole Desktop is acting weird. This one is using an Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] GPU.
Box is 2 * EPYC 7281 with 128 GB ECC RAM
Also a 14C Xeon box with a HD7700 is broken same way.
The hardware is irrelevant for this. We need to know what software stack you use on top of it.
Well, the hardware appears to be part of the issue too. I don't think it's a coincidence that Gabriel has the problem on 2xEPYC, I have it on 2xXeon and the previous reported had it on a Core 2 Quad that internally has two dies.
I've not yet tested your disable CONFIG_SWIOTLB fix yet -- might try it over the weekend and report what happens.
To get that right .. is only a matter of disabling SWIOTLB *code* while CONFIG_SWIOTLB is still set ?
Ok I tested that on 4.16.1 and yes it does work. However I didn't like the #if 0 method and so compile an kernel twice just to compare an test.
I created an small patch and added swiotlb option for amdgpu and radeon so I can boot and compare / test with and without SWIOTLB code.
( not meant for upstream )
http://ftp.frugalware.org/pub/other/people/crazy/0001-Make-it-possible-to-di...
With SWIOTLB code off all works fine , while hell breaks when turning on.
Maybe similar options should be added upstream until code is more stable in 4.17/4.18
Regards