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Date:      Mon, 03 Mar 2014 09:56:25 -0800
From:      Alfred Perlstein <bright@mu.org>
To:        freebsd-arch@freebsd.org
Subject:   Re: newcons fb driver
Message-ID:  <5314C249.9000808@mu.org>
In-Reply-To: <CAJ-Vmokv0r-rTCg15iWKLDcDLR8Hoh0WVgf3CDLNxz%2BONZ5EnQ@mail.gmail.com>
References:  <20140302085511.6354f9ac@zhabar.gateway.2wire.net> <CAJ-Vmo=jCGUxXs_GBoCm581wTouozWE=AQ3x1wBKYM_J3_dGrg@mail.gmail.com> <42130.1393829535@critter.freebsd.dk> <CAJ-Vmokv0r-rTCg15iWKLDcDLR8Hoh0WVgf3CDLNxz%2BONZ5EnQ@mail.gmail.com>

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On 3/2/14, 10:58 PM, Adrian Chadd wrote:
> On 2 March 2014 22:52, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
>> In message <CAJ-Vmo=jCGUxXs_GBoCm581wTouozWE=AQ3x1wBKYM_J3_dGrg@mail.gmail.com>
>> , Adrian Chadd writes:
>>
>>> .. i'm pretty sure there was a reason for why it's done in byte sizes.
>>> Maybe speak to phk?
>> Buggy video hardware, which does not do larger writes correctly,
>> the most recent one being an Intel Laptop, but I can't remember which.
>>
>> At the very least, byte writes needs to be a boot-time option.
> Is there a way to detect this? Ie, writing to video memory and then
> reading it back a byte at a time to see if the patterns match?

I seem to recall this being a technique used back in my 386/msdos days. :)

-Alfred




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