From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Smirl Subject: Multiple drivers for same hardware:, was: DRM and pci_driver conversion Date: Thu, 23 Oct 2003 20:47:01 -0700 (PDT) Sender: linux-fbdev-devel-admin@lists.sourceforge.net Message-ID: <20031024034701.16514.qmail@web14915.mail.yahoo.com> References: <3F987E18.9080606@pobox.com> Mime-Version: 1.0 Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Cipher TLSv1:DES-CBC3-SHA:168) (Exim 3.31-VA-mm2 #1 (Debian)) id 1ACswZ-0001le-00 for ; Thu, 23 Oct 2003 20:48:56 -0700 Received: from web14915.mail.yahoo.com ([216.136.225.228]) by sc8-sf-mx1.sourceforge.net with smtp (Exim 4.22) id 1ACsuv-00084Q-Cm for linux-fbdev-devel@lists.sourceforge.net; Thu, 23 Oct 2003 20:47:13 -0700 In-Reply-To: <3F987E18.9080606@pobox.com> Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jeff Garzik , Linus Torvalds Cc: Jon Smirl , Eric Anholt , kronos@kronoz.cjb.net, Kernel Mailing List , linux-fbdev-devel@lists.sourceforge.net, dri-devel What about the fundamental question? We have several pairs of device drivers that want to control the same hardware. One example would be radeon DRM and radeon Framebuffer. How should these drivers coordinate probing and claiming resources? What should be the policy for multiple drivers? 1) try new probe first and fall back to old scheme. First driver that loads gets the new probe, second gets the old. First driver reserves resources. 2) Require a mini driver that handles probing. Then both drivers attach to the mini driver. 3) Declare it illegal and make the drivers merge. 4) Declare it illegal and only allow first one loaded to run. Right now radeonfb handles probing and resource reservation. DRM works in stealth mode. DRM uses all of the resources and never tells the kernel, that's how it avoids conflicting with framebuffer. DRM and framebuffer trade off control at VT switch. 2D state is save and restored. There is an assumption that framebuffer won't mess with the 3D state. I'm not sure that suspend/resume are coordinated in any way. ===== Jon Smirl jonsmirl@yahoo.com __________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com ------------------------------------------------------- This SF.net email is sponsored by: The SF.net Donation Program. Do you like what SourceForge.net is doing for the Open Source Community? Make a contribution, and help us add new features and functionality. Click here: http://sourceforge.net/donate/