Re: Why is the max_sectors set the 240

[Alan Stern]

On Sat, 24 Sep 2016, Lipengcheng wrote:

> Hi,
> Some special superspeed u3 disk connect xhci control. Then the u3
> disk is read/write and has the Transfer error on endpoint
> (COMP_TX_ERR) error. However in the pc windows does not have the
> problem.By analysis, the windows is each transfer 64K size. The Linux
> is 120K size. In the scsiglue.c, the max_sectors value set the 128
> and each transfer 64K size. Then the Linux system is no problem too.
> Why is the max_sectors set the 240?  May the max_sectors be the other
> values?

Most devices work okay with max_sectors set to 240.  However, you can 
change the value if you want.  Read the usb-storage.quirks section in 
Documentation/kernel-parameters.txt; the m flag will set max_sectors to 
64.

Alan Stern