Hello,
I have a 128 MB SanDisk Cruzer Micro USB key, which is supposed to be fully USB2 compliant. I can't, however, get more than "full speed" (12 Mbps) access to it, even though the EHCI-HCD module does report that the device is in "high speed" mode (480 Mbps). Timing the copy of large files (50-100 MiB) shows that aproximately 11.9 Mbps is achieved.
Here is an excerpt of /proc/bus/usb/devices:
T: Bus=01 Lev=01 Prnt=01 Port=04 Cnt=01 Dev#= 3 Spd=480 MxCh= 0 D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 P: Vendor=0781 ProdID=7112 Rev=20.33 S: Manufacturer=SanDisk Corp. S: Product=Cruzer Micro S: SerialNumber=0000009123 C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
And another excerpt from dmesg:
usb 1-5: new high speed USB device using ehci_hcd and address 3 scsi0 : SCSI emulation for USB Mass Storage devices usb-storage: device found at 3 usb-storage: waiting for device to settle before scanning Vendor: SanDisk Model: Cruzer Micro Rev: 2033 Type: Direct-Access ANSI SCSI revision: 00 SCSI device sda: 256000 512-byte hdwr sectors (131 MB) sda: assuming Write Enabled sda: assuming drive cache: write through
I have tried disabling OHCI-HCD and unplugging every other USB device,
with no success. I have noticed this issue with kernels 2.6.8.1, 2.6.9 and 2.6.10 (released today), as well as with 2.4.x kernels (Knoppix 3.2,
Damn Small Linux 0.9.1).
This is the only USB2 device I own, and I haven't had a chance to try it on another machine yet. My motherboard is an Asus A7N8X Deluxe which is also fully USB2 compliant.
Is this a common issue? What could be wrong in my setup?
-- LFS ID: 7748
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/
_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-users
