From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Smirl Subject: Re: sysfs support for framebuffer Date: Mon, 21 Feb 2005 17:15:35 -0500 Message-ID: <9e473391050221141525aea1ef@mail.gmail.com> References: <9e4733910502181435f60371c@mail.gmail.com> <9e4733910502211133a8d7e59@mail.gmail.com> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1D3Lq8-0007Cx-Qd for linux-fbdev-devel@lists.sourceforge.net; Mon, 21 Feb 2005 14:15:40 -0800 Received: from rproxy.gmail.com ([64.233.170.200]) by sc8-sf-mx2.sourceforge.net with esmtp (Exim 4.41) id 1D3Lq7-0006tP-BC for linux-fbdev-devel@lists.sourceforge.net; Mon, 21 Feb 2005 14:15:40 -0800 Received: by rproxy.gmail.com with SMTP id z35so648319rne for ; Mon, 21 Feb 2005 14:15:36 -0800 (PST) In-Reply-To: Sender: linux-fbdev-devel-admin@lists.sourceforge.net Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: List-Post: List-Help: List-Subscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" To: linux-fbdev-devel@lists.sourceforge.net On Mon, 21 Feb 2005 21:36:38 +0000 (GMT), James Simmons wrote: > Now there is a problem to the above. If we have more than one graphics > card it will get messy. I would guess the X server wants to know what > things belong to what device. For example the matrox card supports dual > heads. What if we have 3 graphics cards. Which two fbX devices belong to the > matrox card. You could scan all the directories and organize a list for > what belongs to what but that would be messy. Plus what if we plug > a monitor in. We have to know which things (fb, mmio) effect its output. I don't see a problem with the current structure. A two headed card would show up as fb0 and fb1. The modelist for fb0 and fb1 would both contain an entry for merged-fb. If you own both devices, then setting the merged-fb mode will simply disable the other device. Same for mirroring. If you don't own both devices the shared modes won't be in the list. Device fb2 would list none of the shared modes. If you really need to know then both fb0 and fb1 are linked to the same device node in sysfs. You are also pointing out a weakness in the fb_info structure. fb_info is not designed for multiple heads. I can copy it like the matrox case but this causes a lot of fields that should not be shared to be copied. A much better design would be to break the structure up into fb_device and fb_head. Then have an fb_head struct for each head. This would also reduce the surface area of what fbcon is seeing since it only needs to see the fb_head structure. -- Jon Smirl jonsmirl@gmail.com ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click