[Bug 107306] [GEN8+] Hang when discarding a fragment if dual source blending is enabled but shader doesn't support it

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=107306

Kenneth Graunke <kenneth at whitecape.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #1 from Kenneth Graunke <kenneth at whitecape.org> ---
Fixed by:

commit 00fc56a68d21d7aa91b95f0eaacba59a96c466f5 (HEAD -> master)
Author: Danylo Piliaiev <danylo.piliaiev at gmail.com>
Date:   Fri Jul 20 12:54:42 2018 +0300

    anv: Disable dual source blending when shader doesn't support it on gen8+

    Dual source blending behaviour is undefined when shader doesn't
    have second color output.

     "If SRC1 is included in a src/dst blend factor and
      a DualSource RT Write message is not used, results
      are UNDEFINED. (This reflects the same restriction in DX APIs,
      where undefined results are produced if “o1” is not written
      by a PS – there are no default values defined)."

    Dismissing fragment in such situation leads to a hang on gen8+
    if depth test in enabled.

    Since blending cannot be gracefully fixed in such case and the result
    is undefined - blending is simply disabled.

    v2 (Jason Ekstrand):
     - Apply the workaround to each individual entry
     - Emit a warning through debug_report

    Signed-off-by: Danylo Piliaiev <danylo.piliaiev at globallogic.com>
    Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
    Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-3d-bugs/attachments/20181030/738e0a2b/attachment.html>