From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NDKwb-0001Er-F0 for qemu-devel@nongnu.org; Wed, 25 Nov 2009 11:42:17 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NDKwW-0001Cd-Nx for qemu-devel@nongnu.org; Wed, 25 Nov 2009 11:42:17 -0500 Received: from [199.232.76.173] (port=46540 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NDKwW-0001Ca-Kr for qemu-devel@nongnu.org; Wed, 25 Nov 2009 11:42:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:12837) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NDKwW-0001iB-8K for qemu-devel@nongnu.org; Wed, 25 Nov 2009 11:42:12 -0500 Date: Wed, 25 Nov 2009 18:42:05 +0200 From: Gleb Natapov Subject: Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios Message-ID: <20091125164205.GP2999@redhat.com> References: <20091123111137.GF2999@redhat.com> <11090DAABE9449F7B5D1415C45F8F411@FSCPC> <20091123194307.GC13854@redhat.com> <2D659FA33BF64C419243FD76049AFD33@FSCPC> <20091124062810.GZ2999@redhat.com> <20091124143812.GA27783@shareable.org> <20091124144044.GJ2999@redhat.com> <20091125060951.GA17203@shareable.org> <20091125122039.GM2999@redhat.com> <20091125153116.GA30957@morn.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091125153116.GA30957@morn.localdomain> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin O'Connor Cc: qemu-devel@nongnu.org, Sebastian Herbszt On Wed, Nov 25, 2009 at 10:31:16AM -0500, Kevin O'Connor wrote: > On Wed, Nov 25, 2009 at 02:20:39PM +0200, Gleb Natapov wrote: > > On Wed, Nov 25, 2009 at 06:09:51AM +0000, Jamie Lokier wrote: > > > But the BIOS must be reloaded from ROM, I'm guessing, if the keyboard > > > controller method is used and the word asking for a branch back to the > > > application has not been set. Because that's how a modern OS (if not > > > using ACPI) asks for a system reset. > > > > > > Do you think the above is (a) correct, and (b) what's implemented? > > > > > Do different things during reset depending on CMOS values doesn't sound > > right to me. I don't know what is implemented right now. I thought that > > we reload BIOS on reset. > > We could have qemu do a soft reset (not reload rom) on a triple fault > or keyboard controller reset, and then have SeaBIOS request a hard > reset (have qemu reload rom) if it detects a soft reset that is not a > "resume" request. > > I'm also not sure what qemu does today. > There is not notion of "soft" reset or "hard" reset in QEMU today. On real modern HW the things are even more complex. There are power planes that can be powered off independently. Think about computer in S3 sleep state. Almost everything is powered of ("hard" reset) except of the memory and RTC. -- Gleb.