Messages in this thread Patch in this message |  | | Date | Sat, 27 Oct 2001 16:10:59 +0200 (MET DST) | From | Mikael Pettersson <> | Subject | [PATCH] arch/i386/boot/bootsect.S incompatibility problem |
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Alan,
The patch below fixes an incompatibility in arch/i386/boot/bootsect.S, which kills Linux' floppy driver on some recent motherboards (e.g. my new ASUS P4T-E Pentium4/I850/S478 mb).
After reading the kernel image, bootsect.S calls kill_motor to stop the floppy drive, which it does by poking port 0x3f2. On the P4T-E, this locks up the FDC, casing drivers/block/floppy to report:
Floppy drive(s): fd0 is 1.44M // long delay here floppy0: no floppy controllers found
drivers/block/floppy.c:reset_fdc() knows about different vintages of FDCs, and uses a different method for non-antique FDCs (poking port 0x3f4 instead). If I use that method in bootsect.S, then the FDC doesn't hang and the floppy driver can identify and use it properly.
However, instead of poking an I/O port there is a BIOS call to reset the FDC: bootsect.S itself uses that call further up, so my patch simply replaces the broken I/O port poke with that BIOS call. Tested on a number of different boxes here, with no breakage observed.
/Mikael
--- linux-2.4.13-ac2/arch/i386/boot/bootsect.S.~1~ Sun Sep 23 21:06:30 2001 +++ linux-2.4.13-ac2/arch/i386/boot/bootsect.S Sat Oct 27 13:35:13 2001 @@ -395,9 +395,15 @@ # NOTE: Doesn't save %ax or %dx; do it yourself if you need to. kill_motor: +#if 1 + xorw %ax, %ax # reset FDC + xorb %dl, %dl + int $0x13 +#else movw $0x3f2, %dx xorb %al, %al outb %al, %dx +#endif ret sectors: .word 0 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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