Mark Lord <mlord@xxxxxxxxx> : [...] > >From tracing through the powerpc arch code, this is the buffer that > is being directly DMA'd into. And the USB layer does an invalidate_dcache > on that entire buffer before initiating the DMA (confirmed via printk). > > The driver itself NEVER writes anything to that buffer, > and nobody else has a pointer to it other than the USB host controller, > so there's nothing else that can write to it either. > > According to the driver writer, the chip should only ever write a fresh > rx_desc struct at the beginning of a buffer, never ASCII data. > > So how does that buffer end up containing ASCII data from the NFS transfers? Through aliasing the URB was given a page that contains said (previously) received file. The ethernet chip/usb host does not write anything in it. There could be a device or a driver problem but it may not be the real problem. So far the analysis focused on "how was this corrupted content written into this receive buffer page ?". If I read David correctly (?) the "nobody else has a pointer to it other than the USB host controller" point may be replaced with "the pointer to it aliases some already used page". -- Ueimor -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
