Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269590AbUISEqr (ORCPT ); Sun, 19 Sep 2004 00:46:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269596AbUISEqr (ORCPT ); Sun, 19 Sep 2004 00:46:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:33719 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S269590AbUISEqY (ORCPT ); Sun, 19 Sep 2004 00:46:24 -0400 Subject: Re: Design for setting video modes, ownership of sysfs attributes From: Benjamin Herrenschmidt To: Jon Smirl Cc: dri-devel , lkml In-Reply-To: <9e47339104091811431fb44254@mail.gmail.com> References: <9e47339104091811431fb44254@mail.gmail.com> Content-Type: text/plain Message-Id: <1095569137.6580.23.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Sun, 19 Sep 2004 14:45:37 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1629 Lines: 38 On Sun, 2004-09-19 at 04:43, Jon Smirl wrote: > Original proposal..... > At OLS we talked about a system like this for setting video modes: > > 1) user owns graphics devices > 2) user sets mode with string (or similar) format using ioctl common to > all drivers. > 3) driver is locked to prevent multiple mode sets > 4) common code takes this string and does a hotplug event with it. > 5) hotplug event runs root context in user space > 6) mode is decoded and verified, this may involve a little process that > maintains the DDC database and reads a file of legal modes. Other > schemes are possible. > 7a) mode is set using VBIOS and vm86, signal driver mode is set > 7b) the register values needed to set the mode are passed into a root > priv ioctl. > 8) driver is unlocked. One issue here... When we discussed all of this with Keith, we wanted a mecanism where the user can set the mode without "owning" the device. Typically, with X: We don't want X itself to have to be the one setting the mode, but rather set the mode and have X be notified properly before and after it happens so it can "catch up". This also involves dealing with all pending DRI clients too, that is they have to be notified that the fb/vmem layout is changing, the pending commands have to be completed, no more accepted, etc... until every DRI "client" acked the change... That sort of thing. Ben. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/