On Wed, Feb 29, 2012 at 1:55 PM, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 2012-02-10 at 00:45 -0800, Dan Williams wrote: >> It is possible for a host to get "locked out" from talking to sata >> devices in the domain if, for example, its sas address changes but the >> expander topology has existing affiliations with the old address. If >> the system is booted userspace can write to >> /sys/class/sas_phy/<phy-X>/hard_reset to clear the affiliation, however >> if this condition exists for the root device the module parameter can be >> used to promote all ata resets to hard resets. > > I don't quite understand this. Are you saying we can't (or shouldn't) > execute > > /sys/class/sas_phy/<phy-X>/hard_reset > > on the root device for some reason? The case I ran into was accidentally changing the host sas address between reboots. If the sata device had been a root device then I would not have been able boot the system. But now that I think about it, if Linux could not boot then neither could the pre-os option-rom/efi driver. >> After the system is booted this state can be cleared via >> /sys/module/libsas/parameters/force_hard_reset > > I really don't think a module parameter for this is such a good idea ... > it effectively promotes all soft resets to being hard ones, which can > have a lot of unintended consequences. Yes, it was only meant as a temporary "get out of a sticky situation" option, but given the above pre-os-driver realization it is not even useful for that case. So I'm fine killing this patch. -- Dan -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
