C&T switching mode difficulties.

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From: Mike Grandin (mike@intrig.com)
Date: Thu 13 Dec 2001 - 22:13:04 IST


I've been experiencing difficulties switching modes with the C&T driver
and a CT69000 based video card.  The initial difficulty seemed that svga
would hang (sometimes) on this code segment from src/vga.c in
vga_setmode(..) : (It'd hang on the second while loop - waiting for the
vertical sync to end).

        /* This is a hack to get around the fact that some C&T chips
         * are programmed to ignore syncronous resets. So if we are
         * a C&T wait for retrace start
         */
      if (__svgalib_getchipset() == CHIPS) {
         while (((port_in(__svgalib_IS1_R)) & 0x08) == 0x08 ) /* wait VSync off */
         while (((port_in(__svgalib_IS1_R)) & 0x08) == 0 ) /* wait VSync on  */
         port_outw(0x07,SEQ_I);         /* reset hsync - just in case...  */
      }

Commenting this section out seemed to resolve the problem, but now it
hangs on gl_fillbox().  The actual function call it's hanging on is
gl_fillbox(50,335,120,6,0).

Any ideas as to why, or a better fix then commenting out the above section in
vga.c, would be appreciated.

Thanks,
--
Mike Grandin

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