On Sun, 23 Nov 2014, liu chunlin wrote: > Hi all, > > AS I known,SDcard use SDIO interface,I need use a sdcard-reader( USB to SDIO)if I want to use sdcard on my board ,but I have try many sdcard-reader without sdcard to connect usb ,all of them will cause usb bus can't enter runtime suspend. and I try to connect a usb storage on my demo board also will cause usb bus can't enter runtime suspend,but if I press power button,the usb bus can enter suspend mode.I guess the driver hav not implemented this function. > > Alan Stern tell me that Runtime suspend for USB storage devices was added in the 3.14 kernel,but I can't find the patches about USB runtime.Who can help me? I was wrong; the support was added in the 3.10 kernel by these commits: 66311274691e 6c9546675864 c8158819d506 9b21493c4520 6df339a51e3b with bug fixes in these commits: d20ec597cba1 c60855cdb976 10c580e4239d In order to make runtime suspend work, you have to turn off media-change polling. When there's no card in the reader, the system will constantly check to see if a card has been inserted. This checking will prevent the device from entering runtime suspend. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
