Very slow umass in 6.2-RC2

JoaoBR joao at
Mon Feb 19 00:48:34 UTC 2007

On Saturday 17 February 2007 09:36, Michael Nottebrock wrote:
> Has anyone ever managed to get some USB 2.0 - like speeds out of ehci
> anyway? I'm not seeing quite such abysmal performance as Kevin did, but I
> don't even need to benchmark to be certain that Windows does *much* better
> with the devices I own. Here are some numbers:
> First up, the controller:
> ehci0: <VIA VT6202 USB 2.0 controller> mem 0xdfffbd00-0xdfffbdff irq
> 21 at device 16.4 on pci0
> usb4: <VIA VT6202 USB 2.0 controller> on ehci0
> usb4: USB revision 2.0
> To be sure the umass device is actually a child of the ehci device:
> dev.umass.0.%parent: uhub4
> dev.uhub.4.%parent: usb4
> This is a Panasonic "Pro High Speed" series 512mb SD-CARD, which
> theoretically supports burst transfer rates up to 20MB/s on a USB 2.0 multi
> card reader:
> da2 at umass-sim0 bus 0 target 0 lun 2
> da2: <Hama CardReaderMMC/SD 1.9C> Removable Direct Access SCSI-0
> device
> da2: 40.000MB/s transfers
> da2: 472MB (967680 512 byte sectors: 64H 32S/T 472C)

I get something between 2-2.5MB when copying from my Sony camera which has a 
1Gb card. It does not matter if I copy 10 or 400Mb it is ever the same. I 
never uploaded anything and have no windows to compare but I ever thought the 
low speed is caused by the device and not by the computer's port. I have a 
MP3 with 512MB no card (integrated memory or something) and I can upload with 
5-6Mb/s to it. It makes no difference if I connect it to ohci or ehci ports. 
Then from my cellphone I never get more than 800kb/s.



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