On Tue, Dec 27, 2011 at 1:21 AM, Jack Wang <jack_wang@xxxxxxxxx> wrote: >> >> In the direct-attached case this routine returns the phy on which this >> device was first discovered. Which is broken if we want to support >> wide-targets, as this phy reference can become stale even though the >> port is still active. >> >> In the expander-attached case this routine tries to lookup the phy by >> scanning the attached sas addresses of the parent expander, and BUG_ONs >> if it can't find it. However since eh and the libsas workqueue run >> independently we can still be attempting device recovery via eh after >> libsas has recorded the device as detached. This is even easier to hit >> now that eh is blocked while device domain rediscovery takes place, and >> that libata is fed more timed out commands increasing the chances that >> it will try to recover the ata device. >> >> Arrange for dev->phy to always point to a last known good phy, it may be >> stale after the port is torn down, but it will catch up for wide port >> reconfigurations, and never be NULL. >> >> Q: How is pm8001_I_T_nexus_reset getting away with not performing reset >> on direct attached sata devices? >> > [Jack Wang] > We found reset may lead to some SATA disks can not be found sometime, in > fact no only for direct attached sata devices. > > I wonder why we always reset the sata device when probe, for pm8001 direct > attached sata firmware will report Initial SATA FIS when phy ready. > We need to get the drive to a known state. Do these problems still happen in your tests with the "wait for ready" checking? That's supposed to allow enough time for the signature fis to be transmitted. I'll take a closer look at your libsas fix, because I believe we are still seeing failures to rediscover all attached devices even with these patches. -- Dan -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
