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Subject: Re: [PATCH v5 2/3] HID: quirks: Refactor ELAN 400 and 401 handling
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Cc:     benjamin.tissoires@redhat.com, jikos@kernel.org,
        bjorn.andersson@linaro.org, lee.jones@linaro.org,
        robh+dt@kernel.org, mark.rutland@arm.com, agross@kernel.org,
        david.brown@linaro.org, hdegoede@redhat.com,
        linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20190606161055.47089-1-jeffrey.l.hugo@gmail.com>
 <20190606161322.47192-1-jeffrey.l.hugo@gmail.com>
 <20190612003507.GG143729@dtor-ws>
From:   Jeffrey Hugo <jhugo@codeaurora.org>
Message-ID: <2282f3e1-e76a-4fe7-d447-51d9a4bee2de@codeaurora.org>
Date:   Wed, 12 Jun 2019 08:29:43 -0600
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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@redhat.com>
>> Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
>> ---
>>   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?