[systemd-devel] Bad accelerometer values cause incorrect screen rotation

[Bastien Nocera]

On Thu, 2019-09-05 at 13:13 +0200, Hans de Goede wrote:
> Hi,
> 
> On 05-09-19 12:49, Bastien Nocera wrote:
> > On Thu, 2019-09-05 at 18:38 +0800, Daniel Drake wrote:
> > > On Thu, Sep 5, 2019 at 6:07 PM Bastien Nocera <hadess at hadess.net>
> > > wrote:
> > > > I've read through this, and I'm happy blacklisting the hp_accel
> > > > driver
> > > > in code. For the other devices, I'd rather leave it as-is.
> > > 
> > > That would indeed avoid most problem cases that I've seen, and
> > > the
> > > current case, probably enough to stop me grumbling for another
> > > year
> > > or
> > > so until this happens again in some other context :)
> > > So I support that idea. Do you have any preference on where we
> > > blacklist it?
> > > 
> > > In the hwdb it's quite easy to match DMI vendor HP & driver
> > > lis3lv02d.
> > > But we'd really want a new way of saying "ignore the
> > > accelerometer"
> > > as
> > > ACCEL_POSITION=base doesn't seem like the right way to express
> > > that.
> > > 
> > > Or we could blacklist it in iio-sensor-proxy but since there's no
> > > mention of hp_accel in the udev properties for the device (you
> > > just
> > > get the driver as li3lv02d) then you'd need to grab the DMI
> > > vendor
> > > name from /sys/class/dmi/id or something like that.
> > > Maybe making this driver export enough data so we can blacklist
> > > it
> > > would be the best way to go about it, along with a new udev
> > > property.
> > 
> > We should make this driver export enough data so we can
> > differentiate
> > it, then we can install a udev property private to iio-sensor-proxy
> > about ignoring specific accelerometers such as this one. This way,
> > the
> > sensor hwdb only contains quirks, not policy decisions about
> > whether
> > the hp_accel driver is worthy.
> 
> I think a good question to ask here is, why do we want to blacklist
> the lis3lv02d when used in HP laptops and I think the answer is
> because it usually sits in the base of the device. So a simpler
> answer
> here might be to just do this:
> 
> diff --git a/hwdb/60-sensor.hwdb b/hwdb/60-sensor.hwdb
> index 3976d9a76a..de5e1b95a2 100644
> --- a/hwdb/60-sensor.hwdb
> +++ b/hwdb/60-sensor.hwdb
> @@ -288,13 +288,6 @@
> sensor:modalias:acpi:KIOX000A*:dmi:bvnAmericanMegatrendsInc.:bvr5.11:
> bd05/25/201
>   # is then applied below.
>   sensor:modalias:platform:lis3lv02d:dmi:*svn*Hewlett-Packard*:*
>    ACCEL_MOUNT_MATRIX=1, 0, 0; 0, 0, -1; 0, 1, 0
> -
> -# HP laptops which have the lis3lv02d device in the base, tell iio-
> sensor-proxy
> -# about this so that the sensor is not used for display orientation
> -sensor:modalias:platform:lis3lv02d:dmi:*svn*Hewlett-
> Packard*:*pnHPProBook4535s*
> - ACCEL_LOCATION=base
> -
> -sensor:modalias:platform:lis3lv02d:dmi:*:svnHewlett-
> Packard:pnHPENVY17NotebookPC:*
>    ACCEL_LOCATION=base
> 
>   sensor:modalias:acpi:SMO8500*:dmi:*:svnHewlett-
> Packard:pnHPStream7Tablet:*
> 
> 
> So in the default hwdb rule for HP laptops with the lis3lv02d sensor
> mark
> the sensor as being in the base.
> 
> This will have the same result as marking it as hp_accel +
> blacklisting
> hp_accel in iio-sensor-proxy. With the added advantage that we can
> whitelist it if we encounter a HP tablet or 2-in-1 where we do
> actually
> want to use it for auto-rotation.
> 
> And this would not require adding any extra code anywhere, so I
> believe
> this would be a nice KISS solution.

That works for me, although the mount matrix would now be wrong and
should probably be removed (or moved).

I'd check the existing entries for tablets and 2-in-1 at the same time
though, and those ones would use the mount matrix, right?