> -----Original Message----- > From: Eric W. Biederman [mailto:ebiederm@xxxxxxxxxxxx] > Sent: Monday, June 26, 2006 2:21 PM > To: Miller, Mike (OS Dev) > Cc: vgoyal@xxxxxxxxxx; Maneesh Soni; Andrew Morton; > Neela.Kolli@xxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; > fastboot@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [Fastboot] [RFC] [PATCH 2/2] kdump: cciss driver > initialization issue fix > > >> "Miller, Mike (OS Dev)" <Mike.Miller@xxxxxx> writes: > >> > >> > Thanks Eric, that helps me understand. Section 8.2.2 of the > >> open cciss > >> > spec supports a reset message. Target 0x00 is the > >> controller. We could > >> > add this to the init routine to ensure the board is made > sane again > >> > but this would drastically increase init time under normal > >> circumstances. > >> > >> Where does the init time penalty come from? How large is the init > >> penalty? I suspect it is from waiting for the scsi disks > to spin up. > >> But I am just guessing in the dark. > > > > The penalty is in the firmware and self-test operations. > > Ok. Reasonable. Roughly long does that take? 1 millisecond? 1 second? > 1 minute? 1 hour? Sorry, roughly 30 to 40 seconds. Maybe longer if the controller thinks there's something wrong with the disks. Typically the disks are always spinning so that delay is not an issue. > > >> > And I suspect this is a hard reset, also. Not sure if that would > >> > negatively impact kdump. If there were some condition we > could test > >> > against and perform the reset when that condition is met it > >> would not > >> > impact 99.9% of users. > >> > >> I am wondering if it is possible to look at the controller > and see if > >> it is in a bad state, (i.e. in some state besides just > coming out of > >> reset) and if so issue a reset. If this really is a long > operation > >> that would be the ideal way to handle it. > > > > It's not really in a bad state at this time, is it? Maybe some > > commands hanging around. > > Not bad as in broken. But bad as in unexpected. If it is > just a matter of outstanding commands we might even be able > to just ask the adapter to cancel all of the at initialization time. We can't detect unexpected but we can discard everything at init. > > > > I was informed of the crashboot command line parameter. I can > > implement that as a test. > > Sounds like a start. > > >> Although it might simply be appropriate to handle commands > completing > >> you didn't start. I am not at all familiar with that particular > >> piece of hardware so I can't make a good guess on what needs to > >> happen there. > > > > Not sure about doing this. > > Well I would certainly print a warning. > > Eric > > - : 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
