On Tue, 2016-01-05 at 10:53 +0200, Jarkko Nikula wrote: > Hi > > On 12/24/2015 04:30 PM, Fu, Zhonghui wrote: > > Now, PM core supports asynchronous suspend/resume mode for devices > > during system suspend/resume, and the power state transition of one > > device may be completed in separate kernel thread. PM core ensures > > all power state transition dependency between devices. This patch > > enables designware i2c controllers to suspend/resume > > asynchronously. > > This will take advantage of multicore and improve system > > suspend/resume > > speed. After enabling all i2c devices, i2c adapters and i2c > > controllers > > on ASUS T100TA tablet, the system suspend-to-idle time is reduced > > to > > about 510ms from 750ms, and the system resume time is reduced to > > about > > 790ms from 900ms. > > > Nice reduction :-) > > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c > > b/drivers/i2c/busses/i2c-designware-platdrv.c > > index 6b00061..395130b 100644 > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > > @@ -230,6 +230,7 @@ static int dw_i2c_plat_probe(struct > > platform_device *pdev) > > } > > > > adap = &dev->adapter; > > + device_enable_async_suspend(&pdev->dev); > > adap->owner = THIS_MODULE; > > adap->class = I2C_CLASS_DEPRECATED; > > ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev- > > >dev)); > > Does device_enable_async_suspend() need to be called before enabling > runtime PM? I suppose not since there appears to have also related > sysfs > node for toggling it runtime. > > I'm thinking if you could move the device_enable_async_suspend() call > into drivers/i2c/busses/i2c-designware-core.c: i2c_dw_probe() and > then > also PCI enumerated adapter could take advantage of it. I concern about Intel BayTrail-T / Braswell / CherryTrail cases, since we have non-trivial PM for LPSS there. Zhonghui, have you a chance to stress test this on platforms based on mentioned SoCs? -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
