From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965694AbbLRB7u (ORCPT ); Thu, 17 Dec 2015 20:59:50 -0500 Received: from mail-ig0-f194.google.com ([209.85.213.194]:34944 "EHLO mail-ig0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965299AbbLRB7r (ORCPT ); Thu, 17 Dec 2015 20:59:47 -0500 MIME-Version: 1.0 In-Reply-To: <1450401390.5427.22.camel@linux.intel.com> References: <1450399868.5427.11.camel@linux.intel.com> <1450401390.5427.22.camel@linux.intel.com> Date: Thu, 17 Dec 2015 17:59:47 -0800 Message-ID: Subject: Re: iio/hid-sensor-accel-3d: no output from /dev/iio:device*? From: Nish Aravamudan To: Srinivas Pandruvada Cc: Jiri Kosina , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald , linux-input@vger.kernel.org, linux-iio@vger.kernel.org, "linux-kernel@vger.kernel.org" , Crt Mori Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 17, 2015 at 5:16 PM, Srinivas Pandruvada wrote: > On Thu, 2015-12-17 at 17:07 -0800, Nish Aravamudan wrote: >> On Thu, Dec 17, 2015 at 4:51 PM, Srinivas Pandruvada >> wrote: >> > On Thu, 2015-12-17 at 15:38 -0800, Nish Aravamudan wrote: >> > > [Starting a new thread from https://lkml.org/lkml/2015/12/15/663, >> > > as >> > > now my laptop is displaying values in the sysfs *raw* files.] >> > > >> > > So I'm trying to understand exactly how the hid-sensor-accel-3d >> > > driver works. >> > > >> > > If I turn up debugging, when I `cat >> > > /sys/bus/iio/devices/device*/*raw*`, I see "iio iio:device3: >> > > accel_3d_proc_event" and I think that means that >> > > hid_sensor_push_data() is getting called. >> > > >> > > But read()'s on /dev/iio:device3 never produces anything, which >> > > is >> > > what iio-sensor-proxy uses to translate events to dbus. >> > > >> > > Is it expected that the dev-node is "silent"? Just trying to >> > > understand if an extension to the driver to support a chardev >> > > based >> > > output is appropriate, or if iio-sensor-proxy needs to be changed >> > > to >> > > handle this device. >> > >> > You are saying there is some regression. This used to work and now >> > it >> > doesn't work. Is raw values are displayed correctly, when you do >> > "cat"? >> > If cat of raw values is working then power on of sensors is >> > working. >> >> Sorry, I was unclear. I don't know if this is a regression. I can try >> going back to an older kernel to see if the /dev/iio:device* files >> produced any output. >> >> Yes, the *raw* files in sysfs are producing output, that is changing >> as I move the laptop around. But the /dev/ nodes seem to produce no >> output (I'm still reading through the driver code to understand where >> that data should be coming from. >> >> > Turn on HID debug prints. If it is regression we can do git bisect. >> > Any ACPI or PM changes can break this. Usually there will be GPIOs >> > which will be involved in power on, where ACPI comes into play. >> > This >> > will be done by i2c-hid. There are some prints in i2c-hid which can >> > be >> > enabled also. >> >> Ok, I will try this, as well. >> > > Try increasing in_accel_sampling_frequency > echo 100 > in_accel_sampling_frequency > Adjust hysteresis to a low value > echo 0 > in_accel_hysteresis > These values are very vendor specific. Adjusting the values in this way didn't seem to make any difference. Also, `cat in_accel_hysteresis` gave EINVAL, but I was able to echo 0 to it. -Nish