On Thu, 17 May 2018, Alexander Kappner wrote: > Oliver and Alan, > > thank for investigating. > > > this is suspicious. You do not actually whether US_FL_NO_WP_DETECT > > by itself would make the device work. Can you please test that? > > US_FL_NO_WP_DETECT without US_FL_IGNORE_UAS does not make a difference, > even with the patch you included applied:
Are you certain Oliver's new code was executed? If you put US_FL_NO_WP_DETECT only in unusual_devs.h and not in ususual_uas.h then it would not affect the uas driver. > > That's bizarre too. Even though the only difference is a MODE SENSE > > command, the command that actually faliled was WRITE(16). > It looks to me like the MODE SENSE simply hangs the drive, so anything > issued after that will fail. Of course the drive says it's the "current > command" that caused the failure, but I wouldn't give too much credence to > that. FYI -- this device is a consumer grade rotational drive that you can > get for less than $200, so I wouldn't be surprised if the implementations > have issues. > > Also, I noticed that copying onto the drive with dd works fine, whereas > trying to mount a filesystem immediately crashes it. I suspect this is > because check_disk_change is called on mount (which eventually calls down > to sd_read_write_protect_flag, which is where the US_FL_NO_WP_DETECT flag > comes into play). Was this tested with uas or usb-storage? Alan Stern
