Changing Console Resolution - Vidcontrol

[Oliver Fromme]

Craig Boston wrote:
 > [...]
 > I only wish 1024x768x4 worked right as (on most cheap video hardware
 > anyway) pushing all the data for 16-bit modes though VESA is quite slow.
 > As it's mostly an IO bandwidth issue, the planar modes should be faster.
 > I can get 800x600x8 working and it's definitely quicker than 800x600x16.

I think 800x600x4 would be even quicker, because no VESA
calls are required at all for screen output.

(All x4 modes use a planar layout.  If such a bitplane is
larger than 64K, so-called bank switching is required to
access all of the video memory, because the VGA address
space allows only a 64K window for access at once.  VESA
calls are required to perform the bank switching.  For
a resolution of 800x600, a bitplane is 60K, so no bank
switching is required, and the whole video memory can be
accessed directly.)

I think FreeBSD's syscons supports it via "flags 0x80"
for the sc device in the kernel config file.  See the
section "Driver Flags" in the sc(4) manual page.

Best regards
   Oliver

PS:  It should be noted that all of that VESA stuff only
works for FreeBSD/i386.  FreeBSD/amd64 isn't capable of
performing calls into the 32bit VESA BIOS.

-- 
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

FreeBSD-Dienstleistungen, -Produkte und mehr:  http://www.secnetix.de/bsd

"A language that doesn't have everything is actually easier
to program in than some that do."
        -- Dennis M. Ritchie