FYI, If you are interested in where I have gotten with this, let me explain:
I have the TL-WN721N plugged into a self powered hub.
I am running on a Freescale iMX50_rd3 EVM.
I have found that the usb disconnect callback does not always get called, for instance on shutdown.
When the device is in the Unresponsive state, I get the folling state output on module load:
usb 2-1.3: ath9k_htc: Transferred FW: htc_9271.fw, size: 51272
ath9k_htc 2-1.3:1.0: ath9k_htc: Target is unresponsive
Failed to initialize the device
usb 2-1.3: ath9k_hif_usb_dev_deinit:1065
ath9k_hif_usb_dev_deinit:1066
usb 2-1.3: ath9k_htc: USB State 7, unplugged = 0, hif_dev->flags = 0
usb 2-1.3: ath9k_htc: USB layer deinitialized
I added the log statement to get the state just before the if statement gating the call to reboot:
As you can see the unplugged if false but HIF_USB_START is not true, therefore the reboot is not called. I am stuck in this state until I unplug the device.
The problem is that I cannot call reboot until hif_usb_start is called.
I tried simplifying the conditional to:
dev_info(&udev->dev, "ath9k_htc: USB State %d, unplugged = %d, hif_dev->flags = %d\n", udev->state, unplugged, hif_dev->flags);
if (!unplugged){
ath9k_hif_usb_reboot(udev);
}
but that just got me:
usb 2-1.3: ath9k_htc: USB State 7, unplugged = 0, hif_dev->flags = 0
ath9k_htc: ath9k_hif_usb_reboot:1200
usb 2-1.3: ath9k_htc: USB reboot failed
usb 2-1.3: ath9k_htc: USB layer deinitialized
So, it may be that the device is not capable of processing the reboot command in this state.
I appologize for my inexperience with the usb apis.
/*----------------------------------------*/
Bob Bouterse
Senior Software Engineer
Multimedia Development Center
D&M Holdings Inc.
http://www.dm-holdings.com
________________________________________
From: Sujith Manoharan [c_manoha@xxxxxxxxxxxxxxxx]
Sent: Monday, May 14, 2012 5:19 AM
To: Bouterse, Robert
Cc: linux-wireless@xxxxxxxxxxxxxxx
Subject: Re: ath9k_htc fails with
Robert Bouterse wrote:
> I seem to running into this same issue, mine is that the driver emits the
> "Target unresponsive" error if the unit is powered-up with the TL-WN721N plugged
> in already. I think my issue is that the USB subsytem event is not recieved by
> the atk9k_htc driver, and therefore the hardware is not reset.
>
> Has this ben fixed already? Can you give me the commit sha1 in wireless-testing?
> I am using compat-wireless, so I am lagging master a bit.
>
> If not, can you point me at where in the driver code the reset happens? Maybe I
> can come up with a patch.
You can play around with the function ath9k_hif_usb_disconnect() in
drivers/net/wireless/ath/ath9k/hif_usb.c which has the deinit/reboot code. :)
Sujith
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