From: Stas Sergeev <stssppnn@yahoo.com>
To: linux-msdos@vger.kernel.org
Subject: Re: please explain to me why video/bios shadowing must be disabled to use graphics... -- Victory!!!
Date: Thu, 17 Oct 2002 19:58:47 +0400 [thread overview]
Message-ID: <3DAEDE37.7050208@yahoo.com> (raw)
Hello.
Bart Oldeman wrote:
>> slower than xdos... why ioperm() doesn't allow
>>>0x3ff ports?..
> Once upon a time Linus decided that a 128 byte per-process i/o bitmap
> is ok, but 8192 bytes is excessively large.
Yes, and there was a reason then, which was
that ISA had 10-bit IO space most likely, but
why it wasn't altered since, is still unclear.
> see also iopl(2)
I don't think it can be used. Even if I trap
int10, do iopl(3), then trap iret and do iopl(0),
it is still dangerous, because pesky vbios calls
some other ints in a mean time.
iopl() is used in ports.c anyway to access that
ports...
I think there is no way around: VESA in WinXP have
the same speed (which means that they also doesn't
have an ability to manipulate the large IO bitmap? -
strange).
next reply other threads:[~2002-10-17 15:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-17 15:58 Stas Sergeev [this message]
2002-10-17 16:29 ` please explain to me why video/bios shadowing must be disabled to use graphics... -- Victory!!! Bart Oldeman
-- strict thread matches above, loose matches on Subject: below --
2002-10-17 6:32 Stas Sergeev
2002-10-17 15:38 ` Bart Oldeman
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