A bit late, but this has bitten us again recently. below are two typos/nitpicks comments
On Mon, Jun 19, 2017 at 11:55:13AM +0200, Benjamin Tissoires wrote: > This is something that bothered us from a long time. When hid-input 'for a long time' > 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 sentence is a bit confusing, needs to be reworded. Acked-by: Peter Hutterer <[email protected]> Cheers, Peter > 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 <[email protected]> > --- > > Hi, > > well, given I'd like to have a formal "go" before spending too much time > in this, I am sending this a an RFC. > This won't solve all the user space problems (especially the detection of > non-mt devices based on ABS_MT_SLOT - 1 being set), but it should help us > extending the other event types. > > Jiri, this patch applies on top of for-next + my series that creates > HID_QUIRK_HAVE_SPECIAL_DRIVER, so do not expect it to apply cleanly on your > tree :) > > Cheers, > Benjamin > > 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 ccdff1e..9a9be89 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -1025,8 +1025,31 @@ 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; > @@ -1527,6 +1550,8 @@ 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]; > @@ -1593,6 +1618,10 @@ int hidinput_connect(struct hid_device *hid, unsigned > int force) > goto out_unwind; > } > > + if (hid->status & HID_STAT_DUP_DETECTED) > + hid_info(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 7a473bf..245d1ac 100644 > --- a/include/linux/hid.h > +++ b/include/linux/hid.h > @@ -340,6 +340,7 @@ 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 > @@ -491,6 +492,7 @@ struct hid_output_fifo { > > #define HID_STAT_ADDED 1 > #define HID_STAT_PARSED 2 > +#define HID_STAT_DUP_DETECTED 3 > > struct hid_input { > struct list_head list; > -- > 2.9.4 >
