> > read: i/o error
>
> i think i see the problem. we're off by one bit.
>
[...]
> /n/sources/plan9//sys/src/9/pc/sdata.c:1344,1350 - sdata.c:1344,1350
> };
>
> static int
> - atageniostart(Drive* drive, vlong lba)
> + atageniostart(Drive* drive, uvlong lba)
> {
> Ctlr *ctlr;
> uchar cmd;
> /n/sources/plan9//sys/src/9/pc/sdata.c:1351,1357 - sdata.c:1351,1357
> int as, c, cmdport, ctlport, h, len, s, use48;
>
> use48 = 0;
> - if((drive->flags&Lba48always) || (lba>>28) || drive->count > 256){
> + if((drive->flags&Lba48always) || (lba>>27) || drive->count > 256){
> if(!(drive->flags & Lba48))
> return -1;
> use48 = 1;
while this does fix the problem, it's sloppy. the problem is actually
that ata reports device sizes as number of sectors+1. it also does not follow
the tradition used for sector counts, where 0 sector count = all-ones+1 = 256.
this is because removable media drives with no media (eg cdroms) give size = 0.
therefore if under any ata addressing scheme, the all-ones sector is not
accessable.
credit to sam hopkins for pointing this out.
/n/sources/plan9//sys/src/9/pc/sdata.c:1344,1350 - sdata.c:1344,1350
};
+ enum{
+ Last28 = (1<<28) - 1 - 1,
+ };
+
static int
- atageniostart(Drive* drive, vlong lba)
+ atageniostart(Drive* drive, uvlong lba)
{
Ctlr *ctlr;
uchar cmd;
/n/sources/plan9//sys/src/9/pc/sdata.c:1351,1357 - sdata.c:1355,1361
int as, c, cmdport, ctlport, h, len, s, use48;
use48 = 0;
- if((drive->flags&Lba48always) || (lba>>28) || drive->count > 256){
+ if((drive->flags&Lba48always) || lba > Last28 || drive->count > 256){
if(!(drive->flags & Lba48))
return -1;
use48 = 1;
- erik
