From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Pandruvada Subject: Re: iio/hid-sensor-accel-3d: no output from /dev/iio:device*? Date: Thu, 17 Dec 2015 17:16:30 -0800 Message-ID: <1450401390.5427.22.camel@linux.intel.com> References: <1450399868.5427.11.camel@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Nish Aravamudan Cc: Jiri Kosina , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald , linux-input-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Crt Mori List-Id: linux-input@vger.kernel.org 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. Thanks, Srinivas > -Nish