From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E6DFC433E9 for ; Thu, 11 Mar 2021 17:39:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1049765002 for ; Thu, 11 Mar 2021 17:39:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229928AbhCKRjR (ORCPT ); Thu, 11 Mar 2021 12:39:17 -0500 Received: from smtp89.ord1c.emailsrvr.com ([108.166.43.89]:45755 "EHLO smtp89.ord1c.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229624AbhCKRjC (ORCPT ); Thu, 11 Mar 2021 12:39:02 -0500 X-Auth-ID: markh@compro.net Received: by smtp20.relay.ord1c.emailsrvr.com (Authenticated sender: markh-AT-compro.net) with ESMTPSA id 57D17E0174; Thu, 11 Mar 2021 12:39:01 -0500 (EST) Reply-To: markh@compro.net Subject: Re: Logitech G602 wireless mouse kernel error messages in 5.10.11+ kernels To: Hans de Goede , =?UTF-8?Q?Filipe_La=c3=adns?= , Jiri Kosina , sashal@kernel.org, Linux-kernel References: <8276a207-abe7-06cc-0c25-f4eebf1a9525@compro.net> <91cda49d4fda10781dc2add8174536cf6b91a527.camel@archlinux.org> From: Mark Hounschell Organization: Compro Computer Svcs. Message-ID: <52838553-0c3f-3a79-2bd7-63dd388b1a5f@compro.net> Date: Thu, 11 Mar 2021 12:39:00 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Classification-ID: a0afc3a9-261a-4615-9b15-2312e0d3e772-1-1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/10/21 4:48 PM, Hans de Goede wrote: > Hi, > > On 3/10/21 9:55 PM, Filipe Laíns wrote: >> On Wed, 2021-03-10 at 15:24 -0500, Mark Hounschell wrote: >>> >>> That is correct, I don't have any buttons bound to keyboard events. With >>> the original patch the G4(forward) and G5(Backward) buttons work in a >>> browser. I guess G7, G8, and G9 buttons are programmable to keyboard events? >>> >>> However this patch does not seem to fix the messages I get. >>> >>> Regards >>> Mark >> >> Those events belong to the USB HID button usage page and are sent by the >> receiver in the HID device with the unnumbered report descriptor, so they are >> not affected. >> >> Looking at the report descriptor for the other HID device, I see a report ID of >> 128 (0x80) used for a vendor application, I am not really sure what it is used >> for and can't seem to trigger my device to send it. >> >> I am gonna guess this is the device reporting the pressed buttons via vendor >> reports or something like that. Speaking as the person who added support for >> this device in libratbag, this report is very likely not something that we don't >> need in our custom drivers and just likely something extra that Logitech built >> to achieve something custom in the Windows driver. FWIW, this device is a very >> weird one, it does not even follow Logitech's own spec :P >> >> Seeing this report the driver chugs. >> >> if (report > REPORT_TYPE_RFREPORT_LAST) { >> hid_err(hdev, "Unexpected input report number %d\n", report); >> return; >> } >> >> Causing your >> >> [ 36.471326] logitech-djreceiver 0003:046D:C537.0002: Unexpected input report number 128 >> [ 36.565317] logitech-djreceiver 0003:046D:C537.0002: Unexpected input report number 128 >> [ 42.390321] logitech-djreceiver 0003:046D:C537.0002: Unexpected input report number 128 >> >> I feel like the correct fix for these cases is not to consume the report and not >> forward it to device node, but rather to forward it to the receiver node. >> >> (looping in Hans) >> Hans, you introduced this code, do you remember why? Where did >> REPORT_TYPE_RFREPORT_LAST get its value from and what is the purpose of this >> check? >> Shouldn't we just keep forwarding unknown reports to the receiver node? Is there >> any technical limitation to do that? I am not too familiar with this part of the >> code. > > The code used by the recvr_type_gaming_hidpp receivers is shared with all the > other non-unifying receivers. Even though these receivers are not unifying the > non gaming versions may still have multiple devices (typically a keyboard + a mouse) > paired with them. > > The standard HID interfaces which these devices emulate are usually split in > at least 2 HID interfaces: > > 1. A keyboard following the requirements of the "boot keyboard" subclass of the > USB HID class, so that the keyboard works inside say the BIOS setup screen. > This uses a single unnumbered HID report > > 2. A mouse + media-keys interface, which delivers numbered reports, including the > special Logitech HID++ reports for things like battery monitoring, but also some > special keys, which have their own sub-addressing embedded inside the reports. > > The driver asks the receiver for a list of paired devices and then builts a list > of devices, which are then instantiated as child-HID devices which are > handled by the drivers/hid/hid-logitech-hidpp.c driver. > > Any input reports received by drivers/hid/hid-logitech-dj.c are then forwarded > to the instantiated child devices, where they are actually processed. > > The problem is that there is not a 1:1 relation between the interfaces and > the instantiated child-devices, so the driver aggregates all input-reports > from both interfaces together and then dispatches / forwards them to the > child-devices using its own internal addressing. > > This forwarding uses 2 different addressing schemes: > > 1. If the report received is a special HID++ report, then it is forwarded to > paired-dev child-dev matching the HID++ device-index which is embedded > inside these special reports. > > 2. If a normal (unnumbered or numbered) report is received then that report is > forwarded based on the report-number. What happens here is that each paired-dev > which the hid-logitech-dj.c code instantiates has a bitmask associated with it > which indicates which kind of reports it consumes. So e.g. a normal mouse will > only consume mouse input-reports (STD_MOUSE, report-id 2) and a keyboard > will consume all of: > > #define STD_KEYBOARD BIT(1) > #define MULTIMEDIA BIT(3) > #define POWER_KEYS BIT(4) > #define MEDIA_CENTER BIT(8) > #define KBD_LEDS BIT(14) > > When forwarding these normal (unnumbered or numbered) reports, the list of > paired devices is searched and the report is forwarded to the first paired-dev > which reports_supported bitmask includes the report-nr: > > spin_lock_irqsave(&djrcv_dev->lock, flags); > for (i = 0; i < (DJ_MAX_PAIRED_DEVICES + DJ_DEVICE_INDEX_MIN); i++) { > dj_dev = djrcv_dev->paired_dj_devices[i]; > if (dj_dev && (dj_dev->reports_supported & BIT(report))) { > logi_dj_recv_forward_report(dj_dev, data, size); > spin_unlock_irqrestore(&djrcv_dev->lock, flags); > return; > } > } > > The: > > if (report > REPORT_TYPE_RFREPORT_LAST) { > hid_err(hdev, "Unexpected input report number %d\n", report); > return; > } > > check happens before this to ensure that report can be represented > as a bitmask, IOW to ensure that BIT(report) does what we expect it to do, > without any wrapping BIT(128) cannot be represented in a 64 bit integer, > so then we end up with undefined behavior. The result will likely be either > 0x00 or 0x01, but it certainly will not do what we want. > > I hope that helps explain why the check is there. > > As for what to do about the errors, I agree with you that the code which is > logging these errors should check for this new special input-reports with > a report-number of 128 and just silently discard these. > > Regards, > > Hans > I am unsubscribing from kernel.org mailing list. I only subscribed to report this issue. Please keep me CC'd to this thread. Thanks Mark