Hi Bart Van Assche, On 2025/2/25 02:11, Bart Van Assche wrote:
lshw is a user space utility. use_192_bytes_for_3f is not exposed to user space as far as I know. So how can the above statement be correct?
Disks have the attribute use_192_bytes_for_3f, which means that disks only accept MODE SENSE transfer lengths of 192 bytes However, when lshw sends MODE SENSE command to disks, use_192_bytes_for_3f will not be considered, which will cause some disks with use_192_bytes_for_3f to be unusableTo solve this problem, it is necessary to determine whether the device has the use_192_bytes_for_3f attribute at the scsi level. If the device has use_192_bytes_for_3f, when lshw or other applications send MODE SENSE command through ioctl, the command with the data length field of 0xff needs to be filtered out to avoid device abnormality.
From include/scsi/scsi_device.h: unsigned use_192_bytes_for_3f:1; /* ask for 192 bytes from page 0x3f */The above code uses use_192_bytes_for_3f for another purpose. Please respect the purpose of the use_192_bytes_for_3f bitfield.Thanks, Bart.
Thanks, -- WangYuli
Attachment:
OpenPGP_0xC5DA1F3046F40BEE.asc
Description: OpenPGP public key
Attachment:
OpenPGP_signature.asc
Description: OpenPGP digital signature
