On Sun, Mar 07, 2021 at 06:58:10AM +0100, Matthias Schwarzott wrote: > Am 05.03.21 um 20:14 schrieb Alan Stern: > > On Fri, Mar 05, 2021 at 05:54:43PM +0100, Matthias Schwarzott wrote: > > > One major difference I noticed looking at service answer time statistics: > > > Windows sends a lot more requests of type "Test Unit Ready". > > > * Windows: 6385 calls > > > * linux: 71 calls > > > > It's generally well known that Windows issues lots and lots of redundant > > commands to USB storage drives. > > > > > > Unless the Kindle advertises removable media, there doesn't seem to be > > any real point to all those TEST UNIT READY commands. Unless they are > > what prevents the disconnections... > > > This is kernel log from connecting: > [41709.248006] usb 3-4: new high-speed USB device number 6 using xhci_hcd > [41709.380015] usb 3-4: New USB device found, idVendor=1949, idProduct=0004, > bcdDevice= 1.00 > [41709.380019] usb 3-4: New USB device strings: Mfr=1, Product=2, > SerialNumber=3 > [41709.380021] usb 3-4: Product: Amazon Kindle > [41709.380022] usb 3-4: Manufacturer: Amazon > [41709.380023] usb 3-4: SerialNumber: REMOVED > [41709.493988] usb-storage 3-4:1.0: USB Mass Storage device detected > [41709.494080] scsi host6: usb-storage 3-4:1.0 > [41710.510122] scsi 6:0:0:0: Direct-Access Kindle Internal Storage > 0100 PQ: 0 ANSI: 2 > [41710.510245] sd 6:0:0:0: Attached scsi generic sg3 type 0 > [41710.513059] sd 6:0:0:0: Power-on or device reset occurred > [41710.526331] sd 6:0:0:0: [sdc] Attached SCSI removable disk > [41712.629152] sd 6:0:0:0: [sdc] 6688768 512-byte logical blocks: (3.42 > GB/3.19 GiB) > [41712.846353] sd 6:0:0:0: [sdc] Write cache: enabled, read cache: enabled, > doesn't support DPO or FUA > [41712.846357] sdc: detected capacity change from 0 to 6688768 > [41712.849499] sdc: sdc1 > > As it prints "Attached SCSI removable disk" the device advertises removable > media. Yes. > > > How can I get further on this topic? > > > > Is runtime power management enabled? Maybe the Kindle disconnects > > whenever the computer tries to suspend it. This typically happens 2 > > seconds after the last command was issued, which matches your > > observations. If runtime PM is enabled, you can try disabling it. > > > I assume this means autosuspend is not used: > > # cat /sys/block/sde/device/power/control > on This means autosuspend isn't used for the sde drive. But the log extract above shows that the Kindle is sdc, not sde. Alan Stern
