RE: A question about ohci_irq()

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Alan,

	Thanks for your reply.
	I have enabled the CONFIG_USB_DEBUG item in the config. So I can get the debug info. 
	Besides the insert and removal of the device, the mouse's action(move etc.) will trigger it. I can understand this point. But What I can not understand is that why the USB disk(Using EHCI) is transferring the files, the ohci_irq() will be triggered?
	From the debug info., I know that the ints value in ohci_irq function equals 0 after and(&) the regs->intrenable.
	Now I am adding an udelay(100us) function in ohci_irq(), and the mouse disconnection issue  can not be found again.

Thanks,
Frank 

-----Original Message-----
From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Alan Stern
Sent: Sunday, December 27, 2009 3:32 AM
To: USB list
Subject: Re: A question about ohci_irq()

On Fri, 25 Dec 2009, Huang, FrankR wrote:

> Hi,all
> 
>        Merry Christmas! Everybody.
>        This issue has puzzled me some time. Can you guys give me a guide.
>        There is an issue using the AMD CS5536 and an MIPS CPU.
>        When transferring files via USB HD , the USB mouse will hang sometimes and lose connection to OHCI Host and this device can not be connected again from then on.

The best way to debug this problem is to enable CONFIG_USB_DEBUG in the 
kernel configuration and check the dmesg log.  Also you can collect a 
usbmon trace to see what's happening at a lower level.

>        I am debugging on this and add some printk() function in ohci_irq() to see OHCI host registers. Very surprising, the USB mouse connection lost issue can not be found. I don't know why. From the debug info, I see the ohci_irq() will be triggered always when I insert the USB HD at the same time, so can you tell me some hints about this? How can I debug that?

ohci_irq() is triggered whenever you plug in a new device or unplug a 
device.  That's because the controller needs to tell the computer when 
something happens, so it raises an interrupt.

Alan Stern

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