I have the same issue that was posted in https://marc.info/?l=linux-usb&m=153295104606185&w=2
Output of 0xb2 and 0xb0 pages is: sg_vpd --page=0xb2 /dev/sda Logical block provisioning VPD page (SBC): Unmap command supported (LBPU): 1 Write same (16) with unmap bit supported (LBWS): 0 Write same (10) with unmap bit supported (LBWS10): 0 Logical block provisioning read zeros (LBPRZ): 0 Anchored LBAs supported (ANC_SUP): 0 Threshold exponent: 1 Descriptor present (DP): 0 Minimum percentage: 0 Provisioning type: 0 Threshold percentage: 0 sg_vpd --page=0xb0 /dev/sda Block limits VPD page (SBC): Write same non-zero (WSNZ): 0 Maximum compare and write length: 0 blocks Optimal transfer length granularity: 8 blocks Maximum transfer length: 65535 blocks Optimal transfer length: 65535 blocks Maximum prefetch length: 65535 blocks Maximum unmap LBA count: 65535 Maximum unmap block descriptor count: 16 Optimal unmap granularity: 0 Unmap granularity alignment valid: 0 Unmap granularity alignment: 0 Maximum write same length: 0x0 blocks Maximum atomic transfer length: 0 Atomic alignment: 0 Atomic transfer length granularity: 0 Maximum atomic transfer length with atomic boundary: 0 Maximum atomic boundary size: 0 According to the link reported by Oliver Neukum, unmap should have been enabled, but it is not. Setting manually the provisioning_mode to unmap enables discard, and after doing some testing, it really works. cat /sys/class/scsi_disk/9\:0\:0\:0/provisioning_mode full echo unmap > /sys/class/scsi_disk/9\:0\:0\:0/provisioning_mode lsblk -D NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO sda 0 4K 4G 0 ├─sda1 0 4K 4G 0 ├─sda2 0 4K 4G 0 So, why it fails to set provisioning_mode to unmap automatically?
