+Cc: dmaengine@ mailing list, Mika On Tue, 2016-11-15 at 14:45 +0100, Thomas Bohn wrote: > Hello, Andriy > > I use an Core m 6Y30 with Linux 4.8.7. And when I boot my computer the > processor clock rate for all four logical cores are 2 GHz and don't > change. > > In powertop I see the interrupt idma64.0 at the top with hundreds or > even more events per seconds. > > When I suspend the computer to RAM and wake it up again, idma64.0 is > gone from powertop and the cpu clocks are at 400 to 500 MHz when the > computer is idling. idma64 itself can't be a culprit of such behaviour. The driver is loaded and bound whenever one of I2C, UART or SPI controllers is enumerated and have DMA capability enabled. So, if you check /proc/interrupt and see what is the counterpart for this DMA IP (some driver with .0 at the end) it would be helpful. For me on the reference design platform I see the following PCI device 00:15.0, which is I2C controller responsible for idma64.0. At the same time interrupt line is shared between idma64.0, i2c, and i801- smbus. The latter is 00:1f.4. 00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21) Status: [D3] Runtime PM: [suspended] 00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21) Status: [D0] Runtime PM: [suspended] Note D0 for the second one. It actually doesn't have any PM support at all. % lspci -vv -nk -s1f.4 | grep D[0-3] ...nothing... Can you try to run % echo 0000:00:1f.4 > /sys/bus/pci/devices/0000\:00\:1f.4/driver/unbind and see what happens? -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
