dwhci: Transaction failed (status 0x82)

[ArnoldUK]

I'm getting hundreds of these dwhci: Transaction failed (status 0x82) messages after a minute or so of booting the kernel. I have a wireless USB keyboard with USB dongle. I running a keyboard raw capture and decoding test kernel using the CUSBKeyboardDevice without any plug and play.

Not seen these messages before and I was curious as to what they mean or what casues them ?

[rsta2]

This indicates an USB Transaction Error (e.g. CRC error, bit stuffing error, timeout), which means something went wrong in a transfer on the USB. This is not a serious error and can be ignored normally. You could try to enable the system option USE_USB_FIQ for a more accurate timing on the USB.

[ArnoldUK]

Cheers for the explaination. I've never seen it before but noticed that it occurs more often when the pi is running alot of code processing in my emulation functions, more often after procesing a raw keyboard handler. I cannot ignore it though as there are hundreds per second and brings the pi to slow crawl (debug messages over serial uart).

I've tried changing usbspeed=full and usbboost=true in cmdline.txt but seems to make it happen more frequently. I will recompile circle with USE_USB_FIQ as I'm using a rpi 1 as I think you also mentioned that this is required for more reliable USB keyboard handling.

EDIT: On a second thought, I'm using the kernel HEX flash method over serial with a USB to serial cable and wondered if this would cause these sort errors ? I only ask this as I've not seen the messages when using the raw kernel copy to the SD-Card and running kernel that way.

Thanks for the super quick support!

[rsta2]

If you do not need the FIQ for other purpose and if it helps, USE_USB_FIQ is a good solution. I don't think, the bootloader can trigger the USB transaction errors. At the time the USB is initialized in the kernel image, the bootloader has no control at all over the RPi any more.

[ArnoldUK]

That appears to have worked now, not a single failed transaction! I must remember to re-compile the circle SDK as I had already defined USE_USB_FIQ but missed the important re-compile..doh.

This is awesome, thanks for your help with this.