From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: KMS cursor BO semantics Date: Fri, 4 Nov 2011 16:34:12 +0100 Message-ID: <20111104153412.GB2933@phenom.ffwll.local> References: <4EB3D3BF.70909@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wy0-f177.google.com (mail-wy0-f177.google.com [74.125.82.177]) by gabe.freedesktop.org (Postfix) with ESMTP id 640169E78F for ; Fri, 4 Nov 2011 08:33:15 -0700 (PDT) Received: by wyf28 with SMTP id 28so3153118wyf.36 for ; Fri, 04 Nov 2011 08:33:14 -0700 (PDT) Content-Disposition: inline In-Reply-To: <4EB3D3BF.70909@vmware.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Thomas Hellstrom Cc: "dri-devel@lists.freedesktop.org" List-Id: dri-devel@lists.freedesktop.org On Fri, Nov 04, 2011 at 12:59:59PM +0100, Thomas Hellstrom wrote: > Hi. > > I have a question about the semantics of the DRM_IOCTL_MODE_CURSOR iotcl: > > Some hardware (vmware's virtual in particular) may not be able to > pick up the changes from a bo directly, since the cursor data is > sent though the command stream. Hence we need a notification when > the cursor image has changed. > > Could we *require* that a cursor image change needs to be followed > by an ioctl call with the flag > DRM_MODE_CURSOR_BO? On i915 we need the cursor in physical memory for some (old) platforms, which is seperate storage from the bo backing storage. So we have the same problem. We've solved it by intercepting pwrite ioctl calls and demanding that userspace only uses these for cursor updates. Is there a special reason you can't use such a driver-specific trick? -Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48