[Bug 164732] cannot read large files from usb flash drive
scitrin at msn.com
Fri Nov 23 18:34:11 UTC 2007
Public bug reported:
Binary package hint: linux-image-2.6-386
Plug in a USB 2.0 flash drive (in this case it was a LEXAR 240 MB
stick). Copy a large, say 200 MB file to the stick from the hard drive.
Now try to access the file either by opening the file with an executable
or trying to copy the file back to another location on the hard drive.
Sometimes the first time you try, this will succeed. On the second and
subsequent attempts to read from the flash drive it will fail....I
believe you are allowed one read for each reboot and then it will
fail...sorry I got a little bit lazy in my testing here. The behavior
is that the read from flash will start, maybe reading the first few
megabytes. Then it will hang for about 2 minutes, finally fail, and
the flash drive will then get automatically and non-gracefully
unmounted. Note that writes to flash are always successful.
This is on Ubuntu Gutsy with all the latest updates. The Linux kernel
version is linux-image-2.6.22-14-generic. The motherboard is a Biostar
nf520-a2 with an NForce520/MCP61D chip set.
You can work around the problem by removing USB 2.0 capability by doing
a "rmmod ehci_hcd" and reverting the system behavior to USB 1.0. (with
subsequent severe performance penalty).
(Please read the whole paragraph before you assume its a hardware
problem!) Interestingly the machine this occurs on is a dual boot
machine. When I did a clean boot of Windows 2000 (that is NOT
virtualized), then the same behavior had occurred in Windows. By
downloading and installing the latest USB 2.0 driver from Biostar (who I
assume got them from NVIDIA), the problem was resolved under Windows.
It appears that the Linux driver also needs to be updated to handle this
For this reason, it possibly appears to be a USB 2.0 driver (ehci_hcd)
problem (possibly specific to this relatively new chip set) which is
why I filed it under Linux Image.
** Affects: linux-meta (Ubuntu)
cannot read large files from usb flash drive
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