On Fri, Jan 11, 2013 at 7:07 PM, Rahul Bedarkar <rpal143@gmail.com> wrote:

Hi,

When I remove pen-drive, I am seeing following logs

[ 132.968942] Disconnect Detected Interrupt++ (Host) a_host [ 133.196692] hub 1-0:1.0: port 1 disabled by hub (EMI?), re-enabling...

So, did you grep for the EMI thingy in the source?

[ 133.207595] usb 1-1: USB disconnect, device number 2 [ 164.420649] sd 0:0:0:0: Device offlined - not ready after error recovery [ 164.447670] sd 0:0:0:0: [sda] Unhandled error code [ 164.459347] sd 0:0:0:0: [sda] Result: hostbyte=0x01 driverbyte=0x00 [ 164.482169] sd 0:0:0:0: [sda] CDB: cdb[0]=0x2a: 2a 00 00 15 65 f8 00 00 08 00 [ 164.643217] end_request: I/O error, dev sda, sector 1402360

Why EMI is coming into picture here ?

I don't know *anything* about USB drivers but hey, I know how to grep my way through. And that is what I did: git grep "EMI?" drivers/usb/ And look what I found in drivers/core/hub.c! /* * EM interference sometimes causes badly * shielded USB devices to be shutdown by * the hub, this hack enables them again. * Works at least with mouse driver. */ Cool.So now you know how EMI came into the picture. Moral of the story: Looking at the code can make you look less foolish. Or perhaps make you more intelligent :)

Thanks, Rahul B.

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