Hi Greg, On Tue, 2010-03-02 at 23:38 +0000, Greg Kroah-Hartman wrote: > When the HDC driver writes the data to the transfer buffers it pollutes > the D-cache (unlike DMA drivers where the device writes the data). If > the corresponding pages get mapped into user space, there are no > additional cache flushing operations performed and this causes random > user space faults on architectures with separate I and D caches > (Harvard) or those with aliasing D-cache. Following the recent discussions in this thread (USB HCD and ARM cache coherency): http://thread.gmane.org/gmane.linux.usb.general/27072 we may no longer need this patch but change the ARM cache handling to assume that any newly allocated page cache page is dirty by default (and the PG_arch_1 bit actually meaning clean rather than dirty). I think it would be better not to push this to mainline until we clarify this in the ARM land. Thanks. -- Catalin -- 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
