From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753030AbdLHTcd (ORCPT ); Fri, 8 Dec 2017 14:32:33 -0500 Received: from mail-io0-f193.google.com ([209.85.223.193]:46765 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752111AbdLHTca (ORCPT ); Fri, 8 Dec 2017 14:32:30 -0500 X-Google-Smtp-Source: AGs4zMYF1V+gXY9I/5a7UGHovugAcdQX6yJEY0DkF7n4GMaz/J2Gw/Raan/Ty2m4WeLXzwmKNXF+Kg== Date: Fri, 8 Dec 2017 11:32:26 -0800 From: Dmitry Torokhov To: Benjamin Tissoires Cc: Jiri Kosina , Peter Hutterer , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] HID: input: do not increment usages when a duplicate is found Message-ID: <20171208193226.74jxj256tg6cwagy@dtor-ws> References: <20171208142818.15156-1-benjamin.tissoires@redhat.com> <20171208142818.15156-3-benjamin.tissoires@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171208142818.15156-3-benjamin.tissoires@redhat.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 08, 2017 at 03:28:18PM +0100, Benjamin Tissoires wrote: > This is something that bothered us from a long time. When hid-input > doesn't know how to map a usage, it uses *_MISC. But there is something > else which increments the usage if the evdev code is already used. > > This leads to few issues: > - some devices may have their ABS_X mapped to ABS_Y if they export a bad > set of usages (see the DragonRise joysticks IIRC -> fixed in a specific > HID driver) > - *_MISC + N might (will) conflict with other defined axes (my Logitech > H800 exports some multitouch axes because of that) > - this prevents to freely add some new evdev usages, because "hey, my > headset will now report ABS_COFFEE, and it's not coffee capable". > > So let's try to kill this nonsense, and hope we won't break too many > devices. > > I my headset case, the ABS_MISC axes are created because of some > proprietary usages, so we might not break that many devices. > > For backward compatibility, a quirk HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE > is created and can be applied to any device that needs this behavior. > > Signed-off-by: Benjamin Tissoires > --- > > changes in v2: > - fixed a bug where the flag was not used properly and prevented to > remove devices > - downgrade the error message from info to debug, given that when > hid-generic binds first, it will output such kernel log for every > multitouch device. > > drivers/hid/hid-input.c | 33 +++++++++++++++++++++++++++++++-- > include/linux/hid.h | 2 ++ > 2 files changed, 33 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > index 04d01b57d94c..31bbeb7019bd 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -1100,8 +1100,31 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel > > set_bit(usage->type, input->evbit); > > - while (usage->code <= max && test_and_set_bit(usage->code, bit)) > - usage->code = find_next_zero_bit(bit, max + 1, usage->code); > + /* > + * This part is *really* controversial: > + * - HID aims at being generic so we should do our best to export > + * all incoming events > + * - HID describes what events are, so there is no reason for ABS_X > + * to be mapped to ABS_Y > + * - HID is using *_MISC+N as a default value, but nothing prevents > + * *_MISC+N to overwrite a legitimate even, which confuses userspace > + * (for instance ABS_MISC + 7 is ABS_MT_SLOT, which has a different > + * processing) > + * > + * If devices still want to use this (at their own risk), they will > + * have to use the quirk HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE, but > + * the default should be a reliable mapping. > + */ > + while (usage->code <= max && test_and_set_bit(usage->code, bit)) { > + if (device->quirks & HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE) { > + usage->code = find_next_zero_bit(bit, > + max + 1, > + usage->code); > + } else { > + device->status |= HID_STAT_DUP_DETECTED; > + goto ignore; > + } > + } > > if (usage->code > max) > goto ignore; > @@ -1610,6 +1633,8 @@ int hidinput_connect(struct hid_device *hid, unsigned int force) > INIT_LIST_HEAD(&hid->inputs); > INIT_WORK(&hid->led_work, hidinput_led_worker); > > + hid->status &= ~HID_STAT_DUP_DETECTED; > + > if (!force) { > for (i = 0; i < hid->maxcollection; i++) { > struct hid_collection *col = &hid->collection[i]; > @@ -1676,6 +1701,10 @@ int hidinput_connect(struct hid_device *hid, unsigned int force) > goto out_unwind; > } > > + if (hid->status & HID_STAT_DUP_DETECTED) > + hid_dbg(hid, > + "Some usages could not be mapped, please use HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE if this is legitimate.\n"); > + > return 0; > > out_unwind: > diff --git a/include/linux/hid.h b/include/linux/hid.h > index 421b62b77c69..de3a8700ccf1 100644 > --- a/include/linux/hid.h > +++ b/include/linux/hid.h > @@ -344,6 +344,7 @@ struct hid_item { > #define HID_QUIRK_SKIP_OUTPUT_REPORT_ID 0x00020000 > #define HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP 0x00040000 > #define HID_QUIRK_HAVE_SPECIAL_DRIVER 0x00080000 > +#define HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE 0x00100000 > #define HID_QUIRK_FULLSPEED_INTERVAL 0x10000000 > #define HID_QUIRK_NO_INIT_REPORTS 0x20000000 > #define HID_QUIRK_NO_IGNORE 0x40000000 Maybe these should be expressed as BIT() also? > @@ -501,6 +502,7 @@ struct hid_output_fifo { > > #define HID_STAT_ADDED BIT(0) > #define HID_STAT_PARSED BIT(1) > +#define HID_STAT_DUP_DETECTED BIT(2) > > struct hid_input { > struct list_head list; > -- > 2.14.3 > -- Dmitry