On 07/25/2013 06:51 PM, Aaron Lu wrote: > On 07/26/2013 07:15 AM, Dave Hansen wrote: >> I've got a relatively new system that doesn't seem to be able to hotplug >> SATA disks. I see the same behavior on 3.10, 3.11-rc2, and Ubuntu's >> 3.8.0-25-generic. The disks are detected right away on reboots, but >> even after poking the /sys/class/scsi_host/host*/scan files, new disks >> are never detected. I've disabled link power management. >> >> Am I doing something stupid here? I thought this "just worked" on my >> previous hardware. > > My vague memory reminds me that not all SATA ports are hot pluggable - > you can check the port's "External SATA port" bit and "Hot Plug Capable" > bit of the PxCMD register like this: > > $ grep ahci /proc/iomem > e1a40000-e1a407ff : ahci > # dd if=/dev/mem of=ahcidump bs=4096 count=1 skip=0xe1a40 > You will need to change 0xe1a40 to decimal format. > > Then the PxCMD is at offset 0x118 for port 0, check bit 21 for E-SATA or > bit 18 for hot pluggable bits. If any of them set to 1, this port > should be hot pluggable; otherwise, it doesn't have this capability. That whole I/O area looks to be 0'd to me, at least for the port if I boot with it unplugged. I even tried toggling the PORT_CMD_ALPE bit with powertop since it is in the same port. Nothing seems to happen for port0 (the one unplugged at boot), although I _can_ see the writes show up for the other ports. I also tried booting with a disk plugged in to a port, then put that disk to sleep and unplugged it. I replugged a _different_ disk in its place, and it was detected just fine. Is it possible that the 'ata_dummy_port_ops' are getting left in place at boot accidentally, that we're mistaking an unplugged port for a disabled one? -- 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
