port 1 disabled by hub (EMI?), re-enabling...
cyberax82 at gmail.com
Fri Jan 11 09:26:26 EST 2013
On Fri, Jan 11, 2013 at 7:07 PM, Rahul Bedarkar <rpal143 at gmail.com> wrote:
> 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=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 :)
> Rahul B.
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