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To: Adrian Chadd <adrian@freebsd.org>
Subject: Re: newcons fb driver
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From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
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Date: Mon, 03 Mar 2014 07:29:23 +0000
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Cc: Justin Hibbits <jhibbits@freebsd.org>,
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In message <CAJ-Vmokv0r-rTCg15iWKLDcDLR8Hoh0WVgf3CDLNxz+ONZ5EnQ@mail.gmail.com>
, Adrian Chadd writes:

>> 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?

Never tried that.

Given that the display was bogus, it would probably work.

Maybe do a "verify" on the first 10 screen updates ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.