[Bug 101651] [radeonsi][hawaii] Borderlands 2 rendering issues with recent mesa/llvm

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=101651

            Bug ID: 101651
           Summary: [radeonsi][hawaii] Borderlands 2 rendering issues with
                    recent mesa/llvm
           Product: Mesa
           Version: git
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Drivers/Gallium/radeonsi
          Assignee: dri-devel at lists.freedesktop.org
          Reporter: ptpzz at yandex.ru
        QA Contact: dri-devel at lists.freedesktop.org

Created attachment 132354
  --> https://bugs.freedesktop.org/attachment.cgi?id=132354&action=edit
screenshot (wrong rendering)

AFAICS it's related to the VCCZ bug. There is a workaround for SI/CIK in the
AMDGPU LLVM backend (SIInsertWaitcnts.cpp) but it doesn't handle this case.

The attached patch fixes it for me by relaxing the workaround condition, but
probably it can be improved if there is a detailed info on that bug. OTOH I
guess it won't have a noticeable effect on performance anyway, so maybe it's
safer to use the patch as is.

The issue is reproducible with the reduced OpenCL test in the attachment:

  $ make

  // run on cpu - reference result

  $ ./testcpu
  117

  // OpenCL/gpu - wrong result

  $ LD_PRELOAD=/opt/llvm64_master/lib/libLLVM-5.0svn.so ./testgpu
  99

  // OpenCL/gpu + patch - correct result

  $ LD_PRELOAD=/opt/llvm64_patched/lib/libLLVM-5.0svn.so ./testgpu
  117

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20170629/6332fcee/attachment-0001.html>