From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@labs.coraid.com>
Date: Fri,  3 May 2013 14:57:12 -0400
To: 9fans@9fans.net
Message-ID: <55d102273818f17528b64eab4ebd9b52@coraid.com>
In-Reply-To: <20130503185151.GA948@polynum.com>
References: <20130423133534.GC19997@polynum.com>
	<39c4acf762ed52f1b9ddfef167d8166a@brasstown.quanstro.net>
	<20130423144653.GB461@polynum.com>
	<84f73a4bc77a38e2f767aff4ef7ac020@coraid.com>
	<20130503185151.GA948@polynum.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Subject: Re: [9fans] Scrolling considered harmful
Topicbox-Message-UUID: 55c032fe-ead8-11e9-9d60-3106f5b1d025

> I have retrieved atom aux/realemu and I will have to test.
>
> But before, I will have to read the aux/vga sources to understand what
> it expects. Because aux/vga -p gives me all the informations about the
> vesa supported modes of the card, and even the monitor settings (I
> wonder that the problem is here, that is monitor and card "discuss" and
> the software is not part of the discussion). The informations (vesa: the
> RADEON card; edid: the monitor 1600x900):

the problem is that the VBE calls that are used to set up
various video modes jump to vendor-provided real mode
code that is often buggy.  the reason for emulation is
(a) to avoid problems associated with real-mode code
triggering interrupts the partial real-mode implementation

the 9 kernels provide is not prepared to handle, and
(b) to avoid invalid accesses caused by buggy real-mode
code.

yes it sounds implausable that the vendor code could be
that broken, but it's true!

- erik