Mike Isely wrote: > Please from http://linuxtv.org/hg/~mcisely/pvrusb2-patches for the > following pvrusb2 driver fixes / improvements: > > - pvrusb2: Minor debug code fixup > - pvrusb2: Fix Gotview hardware support > - pvrusb2: Avoid using stack allocated buffers when performing USB I/O Your comment for this patch is wrong: pvrusb2: The pvrusb2 driver has for the longest time used a (tiny) stack allocated buffer for some of its I/O with the hardware. Apparently later kernels don't like this behavior and trap it at run-time, causing nasty complaints to the kernel log. This trivial change fixes the one case in the driver where this had been happening. It were never valid to use stack for DMA, as kernel provides no warranty that the stack would be on a page that can do DMA. In a matter of fact, as most x86 USB drivers accept DMA at the first 3Gb of RAM space, this bug is generally not noticed on i386/x86_64 archs. Yet, if your machine has more than 3Gb, there are some chances that the stack would be at the HIGHMEM area, where DMA is not supported by the processor. As this is a common error, newer kernels have some instrumentation support to warn about such troubles. I'll be fixing the comment. -- Cheers, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
