Commit 48dd643c authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Linus Torvalds
Browse files

hd.c: remove BIOS/CMOS queries

An ST-506 disk these days is pretty much someone trying to pull ancient
data using an auxilliary controller.  Pulling data from the BIOS or CMOS
is just plain wrong, since it's likely to be the primary OS disk... and
would be user-entered data anyway.  Instead, require the user enters it
on the command line.
Signed-off-by: default avatarH. Peter Anvin <>
Signed-off-by: default avatarLinus Torvalds <>
parent 7f1291f2
......@@ -719,74 +719,25 @@ static int __init hd_init(void)
device_timer.function = hd_times_out;
blk_queue_hardsect_size(hd_queue, 512);
#ifdef __i386__
if (!NR_HD) {
extern struct drive_info drive_info;
unsigned char *BIOS = (unsigned char *) &drive_info;
unsigned long flags;
int cmos_disks;
for (drive=0 ; drive<2 ; drive++) {
hd_info[drive].cyl = *(unsigned short *) BIOS;
hd_info[drive].head = *(2+BIOS);
hd_info[drive].wpcom = *(unsigned short *) (5+BIOS);
hd_info[drive].ctl = *(8+BIOS);
hd_info[drive].lzone = *(unsigned short *) (12+BIOS);
hd_info[drive].sect = *(14+BIOS);
#ifdef does_not_work_for_everybody_with_scsi_but_helps_ibm_vp
if (hd_info[drive].cyl && NR_HD == drive)
BIOS += 16;
We query CMOS about hard disks : it could be that
we have a SCSI/ESDI/etc controller that is BIOS
compatible with ST-506, and thus showing up in our
BIOS table, but not register compatible, and therefore
not present in CMOS.
Furthermore, we will assume that our ST-506 drives
<if any> are the primary drives in the system, and
the ones reflected as drive 1 or 2.
The first drive is stored in the high nibble of CMOS
byte 0x12, the second in the low nibble. This will be
either a 4 bit drive type or 0xf indicating use byte 0x19
for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.
Needless to say, a non-zero value means we have
an AT controller hard disk for that drive.
Currently the rtc_lock is a bit academic since this
driver is non-modular, but someday... ? Paul G.
spin_lock_irqsave(&rtc_lock, flags);
cmos_disks = CMOS_READ(0x12);
spin_unlock_irqrestore(&rtc_lock, flags);
if (cmos_disks & 0xf0) {
if (cmos_disks & 0x0f)
NR_HD = 2;
NR_HD = 1;
#endif /* __i386__ */
#ifdef __arm__
if (!NR_HD) {
/* We don't know anything about the drive. This means
* We don't know anything about the drive. This means
* that you *MUST* specify the drive parameters to the
* kernel yourself.
* If we were on an i386, we used to read this info from
* the BIOS or CMOS. This doesn't work all that well,
* since this assumes that this is a primary or secondary
* drive, and if we're using this legacy driver, it's
* probably an auxilliary controller added to recover
* legacy data off an ST-506 drive. Either way, it's
* definitely safest to have the user explicitly specify
* the information.
printk("hd: no drives specified - use hd=cyl,head,sectors"
" on kernel command line\n");
if (!NR_HD)
goto out;
for (drive=0 ; drive < NR_HD ; drive++) {
struct gendisk *disk = alloc_disk(64);
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