From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C47E0CD4F25 for ; Sat, 16 May 2026 11:37:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AB06910E17D; Sat, 16 May 2026 11:37:26 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MPbcEsl3"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 55F1210E17D; Sat, 16 May 2026 11:37:24 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 7CDC043F06; Sat, 16 May 2026 11:37:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFD8CC19425; Sat, 16 May 2026 11:37:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778931444; bh=8LMT1TIsNVvknyrLg69MYjeZewa0zQXqnKxuS28eL+c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MPbcEsl37NrIoi6gkugdu76RGm+1B1heXb0avm7x3+5zUv3BKP6/+DAud92stKTIy kVV9us91F1CU39b8ftDkbwPgqSfZj9wdQ9o3dELEOwiFS9+rHKDvQMw0oRxHPIFE8N CasPNjOXD9veE4YohlCf8+S1cGeUkKhoENg/gaYk= Date: Sat, 16 May 2026 13:37:28 +0200 From: Greg Kroah-Hartman To: Julian Orth Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , Jonathan Corbet , Shuah Khan , Arnd Bergmann , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-doc@vger.kernel.org, wayland-devel@lists.freedesktop.org Subject: Re: [PATCH 12/12] misc/syncobj: add new device Message-ID: <2026051653-walmart-morally-3be7@gregkh> References: <20260516-jorth-syncobj-v1-0-88ede9d98a81@gmail.com> <20260516-jorth-syncobj-v1-12-88ede9d98a81@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260516-jorth-syncobj-v1-12-88ede9d98a81@gmail.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Sat, May 16, 2026 at 01:06:15PM +0200, Julian Orth wrote: > This device makes the DRM_IOCTL_SYNCOBJ_* ioctls available via a > dedicated device. This allows applications to use syncobjs without > having to open device nodes in /dev/dri, on systems that don't have any > such nodes, or on systems whose devices don't support the > DRIVER_SYNCOBJ_TIMELINE feature. > > Wayland uses syncobjs as its buffer synchronization mechanism. Most > compositors use the DRM_IOCTL_SYNCOBJ_EVENTFD ioctl to perform a pure > CPU wait for syncobj point. DRM devices are not involved in this process > except insofar that a DRM device needs to be used to access the ioctl. > > Similarly, a software-rendered client might perform rendering on a > dedicated thread and use the wayland syncobj protocol to submit frames > before they finish rendering. Again, this does not involve DRM devices > except insofar ... as above. > > As an added benefit, this device removes the need to translate between > file descriptors and handles. > > Signed-off-by: Julian Orth > --- > Documentation/userspace-api/ioctl/ioctl-number.rst | 1 + > drivers/misc/Kconfig | 10 + > drivers/misc/Makefile | 1 + > drivers/misc/syncobj.c | 404 +++++++++++++++++++++ > include/uapi/linux/syncobj.h | 75 ++++ > 5 files changed, 491 insertions(+) > > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst > index 331223761fff..5e140ae5735e 100644 > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst > @@ -395,6 +395,7 @@ Code Seq# Include File Comments > > 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver > 0xCD 01 linux/reiserfs_fs.h Dead since 6.13 > +0xCD 00-0F uapi/linux/syncobj.h > 0xCE 01-02 uapi/linux/cxl_mem.h Compute Express Link Memory Devices > 0xCF 02 fs/smb/client/cifs_ioctl.h > 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/ > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > index 00683bf06258..c1e7749bd356 100644 > --- a/drivers/misc/Kconfig > +++ b/drivers/misc/Kconfig > @@ -644,6 +644,16 @@ config MCHP_LAN966X_PCI > - lan966x-miim (MDIO_MSCC_MIIM) > - lan966x-switch (LAN966X_SWITCH) > > +config SYNCOBJ_DEV > + tristate "DRM syncobj device (/dev/syncobj)" > + depends on DRM If this is a drm-only thing, then please put it in the drm subdirs, not in drivers/misc/ as that would imply that I have to maintain this, not the DRM developers :) thanks, greg k-h