On 8/3/05, Mark Bellon <[EMAIL PROTECTED]> wrote: > Bartlomiej Zolnierkiewicz wrote: > > >Hi, > > > >The topic was discussed to death on linux-kernel. > > > >Mark, you need to fix your applications and stop using /proc/ide/hd*/geometry > >or/and HDIO_GET_GEO ioctl (which BTW your patch also affects). > > > > > Fixing the applications I can understand but the patch still seems > necessary, to me, so the > HDIO_GET_GEO returns "rational" values. > > I tested HDIO_GET_GEO and it returns the same broken values as go into > /proc (no surprises) without my patch.
Please explain. > If a drive is in LBA mode (28 or 48 bit) the existing code doesn't > always "fix up" the geometry properly for some value returns. It only > tries with 48 bit mode and it fails there for some values. My patch > forces a complete geometry and appears (to me) to preserve the side > efefcts of the existing code. > > Am I missing something? diff -Naur linux-2.6.13-rc3-git9-orig/drivers/ide/ide-disk.c linux-2.6.13-rc3-git9/drivers/ide/ide-disk.c --- linux-2.6.13-rc3-git9-orig/drivers/ide/ide-disk.c 2005-08-01 13:48:21.000000000 -0700 +++ linux-2.6.13-rc3-git9/drivers/ide/ide-disk.c 2005-08-02 12:14:43.000000000 -0700 @@ -884,10 +884,17 @@ ide_add_setting(drive, "max_failures", SETTING_RW, -1, -1, TYPE_INT, 0, 65535, 1, 1, &drive->max_failures, NULL); } +static uint32_t do_div64_32 (__u64 n, uint32_t d) +{ + do_div(n, d); + + return n; +} + static void idedisk_setup (ide_drive_t *drive) { struct hd_driveid *id = drive->id; - unsigned long long capacity; + __u64 capacity; int barrier; idedisk_add_settings(drive); @@ -949,27 +956,32 @@ */ capacity = idedisk_capacity (drive); if (!drive->forced_geom) { + uint32_t cylsz, cyl; - if (idedisk_supports_lba48(drive->id)) { - /* compatibility */ - drive->bios_sect = 63; - drive->bios_head = 255; + /* + * In LBA mode the geometry isn't used to talk to the drive + * so always create a "rational" geometry from the capacity. + */ + if (drive->select.b.lba) { why are you forcing drive->bios_sect and drive->bios_head values for LBA28 drives? + drive->bios_sect = drive->sect = 63; + drive->bios_head = drive->head = 255; changing drive->sect and drive->head is just wrong, these are values reported by the device - do not touch them + + cylsz = drive->bios_sect * drive->bios_head; + cyl = do_div64_32(capacity, cylsz); division by zero now is possible (yes, 0/0/0 is possible) + + /* "fake out" works up to ~500 GB */ + cyl = (cyl > 65535) ? 65535 : cyl; + drive->bios_cyl = drive->cyl = cyl; drive->cyl shouldn't be changed } if (drive->bios_sect && drive->bios_head) { - unsigned int cap0 = capacity; /* truncate to 32 bits */ - unsigned int cylsz, cyl; + cylsz = drive->bios_sect * drive->bios_head; + cyl = do_div64_32(capacity, cylsz); - if (cap0 != capacity) - drive->bios_cyl = 65535; cap0 != capacity => set the max possible drive->bios_cyl, no need for adjusting it - else { cap0 == capacity => no need for do_div(), only lower 32-bits are used, adjust drive->bios_cyl - cylsz = drive->bios_sect * drive->bios_head; - cyl = cap0 / cylsz; - if (cyl > 65535) - cyl = 65535; - if (cyl > drive->bios_cyl) - drive->bios_cyl = cyl; - } + if (cyl > 65535) + cyl = 65535; + if (cyl > drive->bios_cyl) + drive->bios_cyl = cyl; } } printk(KERN_INFO "%s: %llu sectors (%llu MB)", > mark > > >Bartlomiej > > > >On 8/3/05, Andre Hedrick <[EMAIL PROTECTED]> wrote: > > > > > >>Did you read ATA-1 through ATA-7 to understand all the variations? > >> > >>On Tue, 2 Aug 2005, Mark Bellon wrote: > >> > >> > >> > >>>The ATA specification tells large disk drives to return C/H/S data of > >>>16383/16/63 regardless of their actual size (other variations on this > >>>return include 15 heads and/or 4092 cylinders). Unfortunately these CHS > >>>data confuse the existing IDE code and cause it to report invalid > >>>geometries in /proc when the disk runs in LBA mode. > >>> > >>>The invalid geometries can cause failures in the partitioning tools; > >>>partitioning may be impossible or illogical size limitations occur. This > >>>also leads to various forms of human confusion. > >>> > >>>I attach a patch that fixes this problem while strongly attempting to > >>>not break any existing side effects and await any comments. > >>> > >>>mark > >>> > >>>Signed-off-by: Mark Bellon <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/