On Tue, 10 Jan 2017, Pali Rohár wrote: > Per Tom Yan suggestion I'm forwarding bug from bugzilla to this ML: > https://bugzilla.kernel.org/show_bug.cgi?id=102271 This really should be sent to the linux-scsi mailing list (CC'ed) as well as to linux-usb. > === Dainius Masiliūnas wrote: === > > When using an Advanced Format drive connected through a SCSI-to-ATA Translation device, the physical > block size reported by the kernel (in /sys/class/block/sdc/queue/physical_block_size) is 512 bytes. > Whereas hdparm -I and smartctl -a do correctly show the physical block size as 4096 bytes. > > In my case, the drive in question is a HGST HTS541075A9E680 hard drive, connected to my PC through a > USB3 HDD enclosure (USB ID 05e3:0731). > > While trying to find more information about this issue, I came across someone else's blog post about > the same issue I'm having, which includes some in-depth analysis: > http://nunix.fr/index.php/linux/7-astuces/65-too-hard-to-be-above-2tb > > It seems that the kernel uses less reliable means to get details about such devices than hdparm > does. Quick summary: READ CAPACITY(10) does not include physical sector size information whereas READ CAPACITY(16) does. But the kernel uses READ CAPACITY(10) by default for USB drives, because quite a few of them die when given a READ CAPACITY(16) command. If you can suggest a way to fix this, we'll be glad to hear it. Alan Stern > I'm using the kernel that's shipped in openSUSE 13.2. > > === Tom Yan replied: === > > It is probably because of this: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/storage/scsiglue.c?h=v4.4#n217 > > SCSI READ CAPACITY (10) will not return "Logical blocks per physical block exponent" like READ > CAPACITY (16) does: > > [tom@localhost ~]$ sudo sg_readcap /dev/sdc > Read Capacity results: > Last logical block address=468862127 (0x1bf244af), Number of blocks=468862128 > Logical block length=512 bytes > Hence: > Device size: 240057409536 bytes, 228936.6 MiB, 240.06 GB > > [tom@localhost ~]$ sudo sg_readcap -16 /dev/sdc > Read Capacity results: > Protection: prot_en=0, p_type=0, p_i_exponent=0 > Logical block provisioning: lbpme=0, lbprz=0 > Last logical block address=468862127 (0x1bf244af), Number of logical blocks=468862128 > Logical block length=512 bytes > Logical blocks per physical block exponent=3 [so physical block length=4096 bytes] > Lowest aligned logical block address=0 > Hence: > Device size: 240057409536 bytes, 228936.6 MiB, 240.06 GB -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
