On 5/25/2016 1:31 AM, Dmitry Torokhov wrote: > On Tue, May 24, 2016 at 3:24 AM, Jiri Kosina <jikos@xxxxxxxxxx> wrote: > >> On Thu, 19 May 2016, Fu, Zhonghui wrote: >> >>> i2c-hid devices' suspend/resume are usually time-consuming process. >>> For example, the touch controller(i2c-ATML1000:00) on ASUS T100 tablet >>> takes about 160ms for suspending and 120ms for resuming. This patch >>> enables i2c-hid devices to suspend/resume asynchronously. This will >>> take advantage of multicore and speed up system suspend/resume process. >> Umm, why do we need this in the first place, given the fact that we are >> enabling async suspend for each and every HID device allocated via >> hid_allocate_device() already? >> > i2c-hid is not a HID but I2C device on I2C bus and is currently resumed > synchronously, in-line. Since it tries to reset device as part of resume it > may take a while for the device to respond. Sorry for late reply. Yes, the devices driven by i2c-hid driver are I2C devices, not HID devices. > > BTW, I am not quite sure what async suspend enabled > in hid_allocate_device() does for us, given that I do not see HID bus > implementing the suspend/resume support for its devices (as far as I > remember we rely on underlying transports - USB or I2C - to resume the > devices properly). Even if HID bus does not implement the suspend/resume support for its devices, the power domain, device type, device class or device driver subsystem related to HID devices can still implement the suspend/resume support for HID devices. Thanks, Zhonghui > > Thanks, > Dmitry > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
