With DMA debugging enabled, I see a warning when the FTDI USB-serial
driver loads [1] using a non-DMAable address.
I can get a disassembly of some of the stack frames to identify the
exact call-sites etc, if that helps anyone?
Thanks,
Daniel
--- [1]
usbcore: registered new interface driver usbserial_generic
usbserial: USB Serial Driver core
USB Serial support registered for FTDI USB Serial Device
ftdi_sio 5-1:1.0: FTDI USB Serial Device converter detected
usb 5-1: Detected FT8U232AM
usb 5-1: Number of endpoints 2
usb 5-1: Endpoint 1 MaxPacketSize 64
usb 5-1: Endpoint 2 MaxPacketSize 64
usb 5-1: Setting MaxPacketSize 64
------------[ cut here ]------------
WARNING: at lib/dma-debug.c:856 check_for_stack+0x9a/0xc0()
Hardware name: OEM
uhci_hcd 0000:00:1d.0: DMA-API: device driver maps memory from stack
[addr=ffff88007f89b946]