Messages in this thread | | | Date | Mon, 03 Oct 2005 11:47:01 -0400 | From | Jeff Garzik <> | Subject | Re: [PATCH 2/3] Add disk hotswap support to libata RESEND #5 |
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Lukasz Kosewski wrote: > On 9/28/05, Jeff Garzik <jgarzik@pobox.com> wrote: > >>>+ dev->flags &= ~ATA_DFLAG_LBA48; >>>+ >> >>probably should just clear out all the flags... > > > I'll look into making this cleaner :) During testing this was the > only one that was necessary, but I'll do some clean-up foo on this. > > >>is ata_chk_err() call in ata_to_sense_error() the only place that needs >>to talk to the hardware? If so, maybe we could work around that by >>making sure it is passed register values, avoiding the need to poke the h/w. > > > Yep, it is the only place as far as I can see. As for passing > register values, the reason I decided not to do that is because, say, > a user unplugged his drive because there WAS some kind of error which > set ATA_ERR. This would attempt to perform some kind of error check > which would compound the problem. However, I agree this is dirty :) > Should I just check the register values, & ~ATA_ERR, and then pass that in? > > >>>+ spin_lock(&ap->host_set->lock); >>>+ hotplug_todo = ap->plug; // Make sure we don't modify while reading! >>>+ spin_unlock(&ap->host_set->lock); >> >>this lock should always be acquired using spin_lock_irqsave() > > > Oops. > > >>>+ ata_scsi_handle_unplug(ap); >>>+ >>>+ // The following flag is necessary on some Seagate drives. >>>+ ap->flags |= ATA_FLAG_SATA_RESET; >> >>we can't unconditionally set this for all controllers >> >>For PATA hotplug, which this code will eventually handle, the SATA >>SControl register doesn't even exist :) > > > if (ap & ATA_FLAG_SATA) ap->flags |= ATA_FLAG_SATA_RESET > ? :) > > >>>+ ap->udma_mask = ap->orig_udma_mask; >> >>dumb question -- what is this for? >> >>for hotplug we'll want to go through the entire probe sequence, >>configuring pio/dma masks all over again. > > > OK I'll admit I may not have looked through the code enough on that > one, but here's a situation I remember about this: > Had a drive which supported UDMA 5 max. Unplugged it, plugged in a > drive which supported UDMA 6, but libata reported UDMA 5 max. Since > the flags aren't reset, and ata_mode_string() works from slowest to > fastest, this will always happen unless we reset the flags to some > default value. So... voila. Do you have a suggestion for making this > cleaner?
Well, overall what needs to happen for newly-plugged-in devices is the a re-run of the probe sequence. The flags should certainly be reset to a default value, the same value that the device would see had it been plugged in when the driver loaded: ata_bus_probe() call sequence, after initialization from ata_host_init(). This may require saving a few pieces of data, as you have done, agreed.
Jeff
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