From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH] Provide control of active VGA device on PCI systems Date: Wed, 23 Feb 2005 07:57:47 +1100 Message-ID: <1109105867.5411.128.camel@gaston> References: <9e47339105021921507545d084@mail.gmail.com> <9e473391050219230764b0dfd2@mail.gmail.com> <200502221050.43534.jbarnes@sgi.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 1D3h74-0004vI-Hd for linux-fbdev-devel@lists.sourceforge.net; Tue, 22 Feb 2005 12:58:34 -0800 Received: from gate.crashing.org ([63.228.1.57]) by sc8-sf-mx2.sourceforge.net with esmtp (TLSv1:AES256-SHA:256) (Exim 4.41) id 1D3h73-0006Nb-07 for linux-fbdev-devel@lists.sourceforge.net; Tue, 22 Feb 2005 12:58:34 -0800 In-Reply-To: <200502221050.43534.jbarnes@sgi.com> 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: Jesse Barnes Cc: Jon Smirl , fbdev On Tue, 2005-02-22 at 10:50 -0800, Jesse Barnes wrote: > Nice, if this is combined with Ben's suggestion of using a firmware loader > type model to deal with POSTing, it seems like we're in pretty good shape. > Can you add documentation for this API to > Documentation/filesystems/sysfs-.txt (maybe the pci file or a new file) > so that userspace people will be able to figure out how to use it? > > Also, how does one know if a card is 'primary' or not? I.e. some BIOSes will > POST all cards, some will POST only one, and some will POST none... Well, that's something we need to figure out... While I do think the POSTing must be under driver control, as I explained, there is still that nasty notion of who has the stuff at 0xc0000 ... and if your firmware runs the x86 BIOS but doesn't keep the shadow around, then you are toast with a good deal of laptop chips. The problem is that on some cards (ATIs for example), the BIOS will modify the image in RAM at c0000 and will put in there various infos, like panel type, PLL infos, etc... that can't always be obtained from the "hard" ROM (especially the panel infos). The driver (raeonfb or X, strace X and see it mmap'ing /dev/mem at c0000...) need those things. Ben. ------------------------------------------------------- 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