CVS commit: src/sys/dev/ata

[David Sainty <dsainty%netbsd.org@localhost>]

Module Name:    src
Committed By:   dsainty
Date:           Sat Jul  2 04:29:01 UTC 2005

Modified Files:
        src/sys/dev/ata: wd.c

Log Message:
Force LBA48 access to ST3160827AS drives.  Without this change the entire
system hangs whenever a read or write request to sector 0xfffffff occurs.

The hang appears to happen when:

status = bus_space_read_1(wdr->cmd_iot, wdr->cmd_iohs[wd_status], 0);

is executed in __wdcwait(), and it is not possible to enter the debugger or
make the system respond at all after this point.

Whilst not necessarily the most prudent solution to handling the large number
of drives that exhibit this problem, it is currently the popular workaround.

[An alternative approach is to just always drop to LBA48 if the request
happens to pass by sector 0xfffffff and the drive reported as larger than
0xfffffff sectors.  My understanding is that the 32 bit addressing below
0x10000000 is purely there as a performance booster, not to resolve a
compatibility issue.]


To generate a diff of this commit:
cvs rdiff -r1.304 -r1.305 src/sys/dev/ata/wd.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.