From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@freedesktop.org Subject: [Bug 101572] glMemoryBarrier is backwards Date: Tue, 27 Jun 2017 16:46:18 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0635037840==" Return-path: Received: from culpepper.freedesktop.org (culpepper.freedesktop.org [IPv6:2610:10:20:722:a800:ff:fe98:4b55]) by gabe.freedesktop.org (Postfix) with ESMTP id 607626E3BF for ; Tue, 27 Jun 2017 16:46:18 +0000 (UTC) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============0635037840== Content-Type: multipart/alternative; boundary="14985819780.cb4d863f.30627"; charset="UTF-8" --14985819780.cb4d863f.30627 Date: Tue, 27 Jun 2017 16:46:18 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.freedesktop.org/ Auto-Submitted: auto-generated https://bugs.freedesktop.org/show_bug.cgi?id=3D101572 --- Comment #2 from Matias N. Goldberg --- That can't be right. You're suggesting that in order to synchronize writes from FBO with a Compu= te Shader I am going to dispatch (which btw the Compute Shader is accessing th= is fbo as a regular sample fetch, not via imageLoad/imageStore) then I either = need to: 1. Switch to a dummy FBO, something that is mentioned nowhere: neither on manuals or online documentation, wikis, or tutorials; also it's not mention= ed to be a guarantee in the spec either. 2. Use a function that was added in OpenGL 4.5; when Compute Shaders were a= dded in 4.3. I may be misinterpreting the spec; but these solution don't make any sense. Best case Mesa should detect that I am trying to read from an FBO in a comp= ute shader being dispatched and issue a barrier for me; worst case one of the functionality already present in 4.3 (like glMemoryBarrier) that doesn't lo= ok esoteric (like switching FBOs) should be enough to synchronize. --=20 You are receiving this mail because: You are the assignee for the bug.= --14985819780.cb4d863f.30627 Date: Tue, 27 Jun 2017 16:46:18 +0000 MIME-Version: 1.0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://bugs.freedesktop.org/ Auto-Submitted: auto-generated

Commen= t # 2 on bug 10157= 2 from Matias N. Goldberg 
That can't be right.

You're suggesting that in order to synchronize writes from FBO with a Compu=
te
Shader I am going to dispatch (which btw the Compute Shader is accessing th=
is
fbo as a regular sample fetch, not via imageLoad/imageStore) then I either =
need
to:

1. Switch to a dummy FBO, something that is mentioned nowhere: neither on
manuals or online documentation, wikis, or tutorials; also it's not mention=
ed
to be a guarantee in the spec either.

2. Use a function that was added in OpenGL 4.5; when Compute Shaders were a=
dded
in 4.3.

I may be misinterpreting the spec; but these solution don't make any sense.
Best case Mesa should detect that I am trying to read from an FBO in a comp=
ute
shader being dispatched and issue a barrier for me; worst case one of the
functionality already present in 4.3 (like glMemoryBarrier) that doesn't lo=
ok
esoteric (like switching FBOs) should be enough to synchronize.

You are receiving this mail because:
  • You are the assignee for the bug.
= --14985819780.cb4d863f.30627-- --===============0635037840== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============0635037840==--