From owner-freebsd-x11@freebsd.org Mon Mar 6 08:48:01 2017 Return-Path: Delivered-To: freebsd-x11@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 23E28CFBF3B for ; Mon, 6 Mar 2017 08:48:01 +0000 (UTC) (envelope-from davshao@gmail.com) Received: from mail-qk0-x243.google.com (mail-qk0-x243.google.com [IPv6:2607:f8b0:400d:c09::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D286B1B06 for ; Mon, 6 Mar 2017 08:48:00 +0000 (UTC) (envelope-from davshao@gmail.com) Received: by mail-qk0-x243.google.com with SMTP id n141so18633633qke.3 for ; Mon, 06 Mar 2017 00:48:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=VQkEkEl13yzvq/7pomL/mFlZJXS3UBtdBCbfvQAfCy8=; b=nNV2CVCzsZgSj/sege2b4F7bkHSkwbq26E41uPEMKcDK+MpsNRiX1/UPtg7Y5rgS1T XNftOLtfMcRj6vpuHC9J42WZ7AWt72VaSTnYl8DNCQnPj/b1VmnRKFb9WxeXmHxwigAf R5kRWIOqB13pDQMeVjHVmC70PhgFTemhjT/1yKlSyqqOkYjWKpHDpxLXLkbm+bQfOlqA 6LpA9sfrO04i2dQj2Nj80jjcclaekwRQ04GRNq9VZQaBq+ROjpYVpYjkHVzeRq5nINeP eQZmqzY6D7fLD277aRDpbqoEB4ILTG35UIMPSiJdV/mA17+Kb9f5YPnvK7lsV2mtVVPi QJaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=VQkEkEl13yzvq/7pomL/mFlZJXS3UBtdBCbfvQAfCy8=; b=QyovczPiYf+wfabXTkWB9h59UGF7/upymNdjvaHFCAeA4GICrACloXpVjULxNOnKTt 9Lb03bkwHi03xQyFpPnv16JIfhvfiZs+rlfs8hZzAXbniXjbrZfK3P/jW6A+qXhI/gxQ fK/VEPK1nF80cR9aoSkox9noIPssQ2HIRVNOkfvwY1mqt3dtsf3yV9dcKsBlWBkUMW9P OnhkSRMCPPimPYhSw3l32Zp61Dod/UBfDT4tJxHzFscutmmq9LwohY9hlja3WEnUo2+1 dFtb+r28oglffmlLPBwTiCq/ZzFMBiOGx8G7xH9Vm22aCb4J7QSgbU2RZ9OwiKmPiX+/ gkfg== X-Gm-Message-State: AMke39l8dI2ZUmK+DPcZeNKzS0NzDd+LewW8y6gQWaxt1ReYcoF+E22HVBvK31vQXdOvNmC8x/XLY2RagWTJeg== X-Received: by 10.55.68.84 with SMTP id r81mr8313363qka.90.1488790079976; Mon, 06 Mar 2017 00:47:59 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.135.129 with HTTP; Mon, 6 Mar 2017 00:47:59 -0800 (PST) From: David Shao Date: Mon, 6 Mar 2017 00:47:59 -0800 Message-ID: Subject: libdrm atomic_add_unless may reverse meaning To: freebsd-x11@freebsd.org Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-x11@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: X11 on FreeBSD -- maintaining and support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 Mar 2017 08:48:01 -0000 For those who have frustrating glitches with applications such as glxgears on Intel integrated graphics, the following libdrm bug report may be of interest. https://bugs.freedesktop.org/show_bug.cgi?id=100077 "libdrm atomic_add_unless() may reverse return value meaning" A one character patch allows glxgears to run on DragonFly using a hacked version of pkgsrc on an Intel IvyBridge integrated graphics machine. --- xf86atomic.h.orig 2015-09-22 04:34:51.000000000 +0000 +++ xf86atomic.h @@ -111,7 +111,7 @@ static inline int atomic_add_unless(atom c = atomic_read(v); while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c) c = old; - return c == unless; + return c != unless; } #endif