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With buggy int13 ah=15, we can mis-identify the floppy devices.

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We have no option than trust INT13 ah=08 return code during the init phase.

PR:		234460
Reported by:	Oleh Hushchenkov
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D18723
This commit is contained in:
Toomas Soome 2019-01-05 07:20:00 +00:00
parent e65e209520
commit a9f7119bb8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=342785
1 changed files with 41 additions and 3 deletions
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44
stand/i386/libi386/biosdisk.c
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@ -136,6 +136,8 @@ static int bd_ioctl(struct open_file *f, u_long cmd, void *data);
static int bd_print(int verbose);
static int cd_print(int verbose);
static int fd_print(int verbose);
static void bd_reset_disk(int);
static int bd_get_diskinfo_std(struct bdinfo *);
struct devsw biosfd = {
.dv_name = "fd",
@ -251,21 +253,53 @@ bd_unit2bios(struct i386_devdesc *dev)
return (-1);
}
/*
* Use INT13 AH=15 - Read Drive Type.
*/
static int
fd_count(void)
{
int drive;
for (drive = 0; drive < MAXBDDEV; drive++) {
bd_reset_disk(drive);
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x1500;
v86.edx = drive;
v86int();
if (V86_CY(v86.efl))
break;
if ((v86.eax & 0x300) == 0)
break;
}
return (drive);
}
/*
* Quiz the BIOS for disk devices, save a little info about them.
*/
static int
fd_init(void)
{
int unit;
int unit, numfd;
bdinfo_t *bd;
for (unit = 0; unit < MAXBDDEV; unit++) {
numfd = fd_count();
for (unit = 0; unit < numfd; unit++) {
if ((bd = calloc(1, sizeof(*bd))) == NULL)
break;
bd->bd_sectorsize = BIOSDISK_SECSIZE;
bd->bd_flags = BD_FLOPPY;
bd->bd_unit = unit;
if (!bd_int13probe(bd)) {
/* Use std diskinfo for floppy drive */
if (bd_get_diskinfo_std(bd) != 0) {
free(bd);
break;
}
@ -382,6 +416,10 @@ bc_add(int biosdev)
static int
bd_check_extensions(int unit)
{
/* do not use ext calls for floppy devices */
if (unit < 0x80)
return (0);
/* Determine if we can use EDD with this device. */
v86.ctl = V86_FLAGS;
v86.addr = 0x13;