AGPSTAT2_4X
if (!((*bridge_agpstat & AGPSTAT2_4X) && (*vga_agpstat & AGPSTAT2_4X) && (*requested_mode & AGPSTAT2_4X)))
*bridge_agpstat &= ~AGPSTAT2_4X;
if (*bridge_agpstat & AGPSTAT2_4X)
*bridge_agpstat &= ~(AGPSTAT2_1X | AGPSTAT2_4X); /* 2X */
*bridge_agpstat &= ~(AGPSTAT2_2X | AGPSTAT2_4X); /* 1X */
*bridge_agpstat &= ~(AGPSTAT2_2X | AGPSTAT2_4X);
if (*requested_mode & AGPSTAT2_4X) {
*requested_mode &= ~AGPSTAT2_4X;
*requested_mode &= ~(AGPSTAT2_4X | AGPSTAT2_2X | AGPSTAT2_1X);
*bridge_agpstat &= ~(AGPSTAT2_2X | AGPSTAT2_4X);
command &= ~AGPSTAT2_4X;