Re: [PATCH v5 2/3] HID: quirks: Refactor ELAN 400 and 401 handling

[Jeffrey Hugo]

On 6/12/2019 8:37 AM, Lee Jones wrote:
> On Wed, 12 Jun 2019, Jeffrey Hugo wrote:
>
> > On 6/11/2019 6:35 PM, Dmitry Torokhov wrote:
> > > On Thu, Jun 06, 2019 at 09:13:22AM -0700, Jeffrey Hugo wrote:
> > > > There needs to be coordination between hid-quirks and the elan_i2c driver
> > > > about which devices are handled by what drivers.  Currently, both use
> > > > whitelists, which results in valid devices being unhandled by default,
> > > > when they should not be rejected by hid-quirks.  This is quickly becoming
> > > > an issue.
> > > >
> > > > Since elan_i2c has a maintained whitelist of what devices it will handle,
> > > > use that to implement a blacklist in hid-quirks so that only the devices
> > > > that need to be handled by elan_i2c get rejected by hid-quirks, and
> > > > everything else is handled by default.  The downside is the whitelist and
> > > > blacklist need to be kept in sync.
> > > >
> > > > Suggested-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> > > > Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@xxxxxxxxx>
> > > > ---
> > > >    drivers/hid/hid-quirks.c | 78 ++++++++++++++++++++++++++++++++++------
> > > >    1 file changed, 67 insertions(+), 11 deletions(-)
> > > >
> > > > diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
> > > > index e5ca6fe2ca57..edebd0700e3d 100644
> > > > --- a/drivers/hid/hid-quirks.c
> > > > +++ b/drivers/hid/hid-quirks.c
> > > > @@ -912,8 +912,66 @@ static const struct hid_device_id hid_mouse_ignore_list[] = {
> > > >    	{ }
> > > >    };
> > > > +/*
> > > > + * List of device names that elan_i2c is handling and HID should ignore.  Must
> > > > + * be kept in sync with elan_i2c
> > > > + */
> > > > +static const char *hid_elan_i2c_ignore[] = {
> > >
> > > If this is a copy of elan whitelist, then, if we do not want to bother
> > > with sharing it in object form (as a elan-i2c-ids module), can we at
> > > least move it into include/linux/input/elan-i2c-ids.h and consume from
> > > hid-quirks.c?
> >
> > I can put it in a shared header file, however elan-i2c and hid-quirks
> > would need to be updated in the same change to prevent a breakage, but
> > that would seem to violate a concern Benjamin brought up in v4 given
> > that elan-i2c is maintained in your input tree, and hid-quirks is
> > maintained in his hid tree.
> >
> > Are you ok with the elan-i2c changes going through Benjamin's hid tree?
>
> We co-ordinate cross-subsystem merges all the time.  That is never a
> reason to not do the 'right thing (tm)'.  If this information can be
> held in a single, central place, without the need for constant
> re-alignment, I'm all for it.

I'm aware coordination is a thing.  I'm trying to elicit some 
coordination between Dmitry and Benjamin.