Messages in this thread |  | | | From | Bartlomiej Zolnierkiewicz <> | | Subject | Re: [PATCH] barrier patch set | | Date | Sat, 20 Mar 2004 17:03:30 +0100 |
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On Saturday 20 of March 2004 03:53, Johannes Stezenbach wrote: > Bartlomiej Zolnierkiewicz wrote: > > On Saturday 20 of March 2004 02:48, Johannes Stezenbach wrote: > > > hdparm -i and -I ultimately both interpret WIN_IDENTIFY result, and > > > both test bit 0x0020 of word 85. So it's unclear to me why they report > > > a different write cache setting. I added a hexdump to dump_identity() > > > in hdparm.c, and found that bit 0x0020 of word 85 is always set. > > > > or WIN_PIDENTIFY to be strict but > > > > -i returns _cached_ (read when the device was probed) identify data > > (uses HDIO_GET_IDENTIFY ioctl) > > -I reads _current_ data directly from the device > > (uses HDIO_DRIVE_CMD ioctl) > > Oh, right. > > But: HDIO_GET_IDENTITY returns drive->id, and surely drive->id > is used internally. So isn't it a bug that drive->id is not > updated when the write cache setting is changed?
No, drive->id shouldn't be changed.
> I think the barrier code uses drive->id to determine if the > write cache is enabled.
The barrier code depends on drive->wcache.
Regards, Bartlomiej
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