From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 28 May 2008 19:34:40 +0100 From: Digby Tarvin To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-ID: <20080528183439.GA8756@skaro.cthulhu.dircon.co.uk> References: <13426df10805271502s7e78ba0dw826dd2f6d982304c@mail.gmail.com> <20080528000641.GA2649@skaro.cthulhu.dircon.co.uk> <775b8d190805280031x17e2f483s1f82640bacd4851f@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <775b8d190805280031x17e2f483s1f82640bacd4851f@mail.gmail.com> User-Agent: Mutt/1.4.1i Subject: [9fans] OT: supporting multiple VGA cards (was "A shot in the dark") Topicbox-Message-UUID: ae04ec70-ead3-11e9-9d60-3106f5b1d025 On the subject of diagnostic tools (this is not specifically a Plan9 issue, but someone on this list might know...): I am interested in connecting more than one graphics adapter so that one can be dedicated to low level diagnostics (rather than the more usual dual head user interface).. but I am not sure how the hardware deals with that given that the VGA standard seems to imply that all the cards would be using identical memory addresses and IO ports. Otherwise I would expect PCI to be able to automatically map resources to non-conflicting addresses/IO ports. In any case my BIOS has a setting which allows selection between AGP and PCI as 'primary' Video, suggesting that it is indeed possible to have at least one of each. The only thing I can think of is that perhaps the VGA/CGA/EGA etc modes are suppressed in the non-primary card, leaving only the more advanced and less standard mode available. But this would be less ideal, as text mode would be more useful for low overhead diagnostics. Does anyone know what actually happens? Regards, DigbyT On Wed, May 28, 2008 at 05:31:27PM +1000, Bruce Ellis wrote: > When I did the port to the PS2 there wasn't even a light to blink. To > get thru l.s I discovered a register I could write that resets the > video. > > Only a hundred lines (most innocent) to binary chop. > > Ken has a better tale of a device that only had a speaker and > debugging by tones. > > brucee > > On 5/28/08, Paul Lalonde wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > FWIW, we used a similar technique just last summer debugging some PS3 -- Digby R. S. Tarvin digbyt(at)digbyt.com http://www.digbyt.com