On 1/5/2016 8:14 PM, Andy Shevchenko wrote: > 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? Because of long leave, so sorry for late reply. I understand what you said, if enable all LPSS devices suspend/resume asynchronously, the system can't resume sometimes on ASUS T100TA(BayTrail-T SoC). But, I have verified that the system can resume normally every time if enable only i2c controller async mode and let other LPSS devices in sync mode on ASUS T100TA. I have no Braswell and cherryTrail platforms, so no verification test on them. I have submitted a new version of this patch to move the device_enable_async_suspend() call into i2c_dw_proble() function - "[PATCH v2] i2c/designware: enable i2c controller to suspend/resume asynchronously". Thanks, Zhonghui > > -- 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
