From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeffrey Hugo Subject: Re: [PATCH v6 2/5] HID: quirks: Refactor ELAN 400 and 401 handling Date: Wed, 19 Jun 2019 11:40:28 -0600 Message-ID: <8cd10509-6a67-7c5b-9139-89bdcaa35f3f@codeaurora.org> References: <20190612212604.32089-1-jeffrey.l.hugo@gmail.com> <20190612212721.32195-1-jeffrey.l.hugo@gmail.com> <20190612214636.GA40779@dtor-ws> <84e7d83f-e133-0281-612a-94d8c4319040@codeaurora.org> <20190619171010.24c25oenpmjpiayw@penguin> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190619171010.24c25oenpmjpiayw@penguin> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Torokhov Cc: Jeffrey Hugo , benjamin.tissoires@redhat.com, jikos@kernel.org, hdegoede@redhat.com, bjorn.andersson@linaro.org, agross@kernel.org, lee.jones@linaro.org, xnox@ubuntu.com, robh+dt@kernel.org, mark.rutland@arm.com, linux-input@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org On 6/19/2019 11:10 AM, Dmitry Torokhov wrote: > On Wed, Jun 12, 2019 at 04:20:42PM -0600, Jeffrey Hugo wrote: >> On 6/12/2019 3:46 PM, Dmitry Torokhov wrote: >>> On Wed, Jun 12, 2019 at 02:27:21PM -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, >>>> which is now in a header file that hid-quirks can access, 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. >>>> >>>> Suggested-by: Benjamin Tissoires >>>> Signed-off-by: Jeffrey Hugo >>>> --- >>>> drivers/hid/hid-quirks.c | 27 ++++++++++++++++----------- >>>> 1 file changed, 16 insertions(+), 11 deletions(-) >>>> >>>> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c >>>> index e5ca6fe2ca57..bd81bb090222 100644 >>>> --- a/drivers/hid/hid-quirks.c >>>> +++ b/drivers/hid/hid-quirks.c >>>> @@ -16,6 +16,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> #include "hid-ids.h" >>>> @@ -914,6 +915,8 @@ static const struct hid_device_id hid_mouse_ignore_list[] = { >>>> bool hid_ignore(struct hid_device *hdev) >>>> { >>>> + int i; >>>> + >>>> if (hdev->quirks & HID_QUIRK_NO_IGNORE) >>>> return false; >>>> if (hdev->quirks & HID_QUIRK_IGNORE) >>>> @@ -978,18 +981,20 @@ bool hid_ignore(struct hid_device *hdev) >>>> break; >>>> case USB_VENDOR_ID_ELAN: >>>> /* >>>> - * Many Elan devices have a product id of 0x0401 and are handled >>>> - * by the elan_i2c input driver. But the ACPI HID ELAN0800 dev >>>> - * is not (and cannot be) handled by that driver -> >>>> - * Ignore all 0x0401 devs except for the ELAN0800 dev. >>>> + * Blacklist of everything that gets handled by the elan_i2c >>>> + * input driver. This avoids disabling valid touchpads and >>>> + * other ELAN devices. >>>> */ >>>> - if (hdev->product == 0x0401 && >>>> - strncmp(hdev->name, "ELAN0800", 8) != 0) >>>> - return true; >>>> - /* Same with product id 0x0400 */ >>>> - if (hdev->product == 0x0400 && >>>> - strncmp(hdev->name, "QTEC0001", 8) != 0) >>>> - return true; >>>> + if ((hdev->product == 0x0401 || hdev->product == 0x0400)) { >>>> + for (i = 0; strlen(elan_acpi_id[i].id); ++i) >>>> + if (!strncmp(hdev->name, elan_acpi_id[i].id, >>>> + strlen(elan_acpi_id[i].id))) >>>> + return true; >>>> + for (i = 0; strlen(elan_of_match[i].name); ++i) >>>> + if (!strncmp(hdev->name, elan_of_match[i].name, >>>> + strlen(elan_of_match[i].name))) >>>> + return true; >>> >>> Do we really need to blacklist the OF case here? I thought that in ACPI >>> case we have clashes as HID gets matched by elan_i2c and CID is matched >>> by i2c-hid, but I do not believe we'll run into the same situation on OF >>> systems. >> >> I think its the safer approach. >> >> On an OF system, such as patch 3 in the series, the "hid-over-i2c" will end >> up running through this (kind of the whole reason why this series exists). >> The vendor and product ids will still match, so we'll end up going through >> the lists to see if the hdev->name (the compatible string) will match the >> blacklist. "hid-over-i2c" won't match the blacklist, but if there is a more >> specific compatible, it might. >> >> In that case, not matching OF would work, however how it could break today >> is if both "hid-over-i2c" and "elan,ekth3000" were listed for the same >> device, and elan_i2c was not compiled. In that case, if we skip the OF part >> of the black list, hid-quirks will not reject the device, and you'll >> probably have some odd behavior instead of the obvious "the device doesn't >> work because the correct driver isn't present" behavior. >> >> While that scenario might be far fetched since having both "hid-over-i2c" >> and "elan,ekth3000" probably violates the OF bindings, its still safer to >> include the OF case in the blacklist against future scenarios. > > Yes, I believe it is quite far fetched. We are talking about someone > setting compatible sting to something that is decidedly not compatible. > I.e. we know that devices driven by elan_i2c are not compatible with > hi-over-i2c driver/protocol, so why do we expect that they both will be > specified in the same compatible string? I know ACPI case is messier in > this regard as 2 drivers look at the different data items when > evaluating whether they should bind to the device, but here we are > dealing with the same string. Alright. Sounds like you really want the DT matching dropped, so I'll update the series with a new version ASAP that drops that.