On Tue, Feb 14, 2017 at 05:32:11PM -0200, Mauro Carvalho Chehab wrote: > Reported as a Kaffeine bug: > https://bugs.kde.org/show_bug.cgi?id=375811 > > The USB control messages require DMA to work. We cannot pass > a stack-allocated buffer, as it is not warranted that the > stack would be into a DMA enabled area. > > On Kernel 4.9, the default is to not accept DMA on stack anymore. > > Tested with USB ID 2040:5510: Hauppauge Windham > > Cc: sta...@vger.kernel.org # For 4.9+
Unless there is some major reason, this should go into _all_ stable releases, as the driver would be broken on them all for platforms that can't handle USB data that is not DMA-able. This has been a requirement for USB drivers since the 2.2 days. thanks, greg k-h
