On 04/08/2014 11:57 PM, Mikulas Patocka wrote: > upstream commit e20e1d0ac02308e2211306fc67abcd0b2668fb8b > Author: Mikulas Patocka <mpatocka@xxxxxxxxxx> > Date: Wed Dec 11 19:38:32 2013 -0500 > > powernow-k6: disable cache when changing frequency > > I found out that a system with k6-3+ processor is unstable during network > server load. The system locks up or the network card stops receiving. The > reason for the instability is the CPU frequency scaling. > > During frequency transition the processor is in "EPM Stop Grant" state. > The documentation says that the processor doesn't respond to inquiry > requests in this state. Consequently, coherency of processor caches and > bus master devices is not maintained, causing the system instability. > > This patch flushes the cache during frequency transition. It fixes the > instability. > > Other minor changes: > * u64 invalue changed to unsigned long because the variable is 32-bit > * move the logic to set the multiplier to a separate function > powernow_k6_set_cpu_multiplier > * preserve lower 5 bits of the powernow port instead of 4 (the voltage > field has 5 bits) > * mask interrupts when reading the multiplier, so that the port is not > open during other activity (running other kernel code with the port open > shouldn't cause any misbehavior, but we should better be safe and keep > the port closed) > > This patch should be backported to all stable kernels. If it doesn't > apply cleanly, change it, or ask me to change it. Thanks, all 3 now applied to 3.12. -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html