Re: [PATCH 1/2] HID: input: make sure the wheel high resolution multiplier is set

Benjamin Tissoires
2019-04-24T13:30:39Z

On Tue, Apr 23, 2019 at 5:46 PM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Some old mice have a tendency to not accept the high resolution multiplier.
> They reply with a -EPIPE which was previously ignored.
>
> Force the call to resolution multiplier to be synchronous and actually
> check for the answer. If this fails, consider the mouse like a normal one.
>
> Fixes: 2dc702c991e377 ("HID: input: use the Resolution Multiplier for
> high-resolution scrolling")
> Link: https://bugzilla.redhat.com/show_bug.cgi?id=1700071
> Reported-and-tested-by: James Feeney <james@nurealm.net>
> Cc: stable@vger.kernel.org # v5.0+
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---

Given that this basically breaks a basic functionality of many
Microsoft mice, I went ahead and applied this series to
for-5.1/upstream-fixes

Cheers,
Benjamin

> drivers/hid/hid-core.c | 7 +++-
> drivers/hid/hid-input.c | 81 +++++++++++++++++++++++++----------------
> include/linux/hid.h | 2 +-
> 3 files changed, 56 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 76464aabd20c..92387fc0bf18 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -1637,7 +1637,7 @@ static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
> * Implement a generic .request() callback, using .raw_request()
> * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
> */
> -void __hid_request(struct hid_device *hid, struct hid_report *report,
> +int __hid_request(struct hid_device *hid, struct hid_report *report,
> int reqtype)
> {
> char *buf;
> @@ -1646,7 +1646,7 @@ void __hid_request(struct hid_device *hid, struct hid_report *report,
>
> buf = hid_alloc_report_buf(report, GFP_KERNEL);
> if (!buf)
> - return;
> + return -ENOMEM;
>
> len = hid_report_len(report);
>
> @@ -1663,8 +1663,11 @@ void __hid_request(struct hid_device *hid, struct hid_report *report,
> if (reqtype == HID_REQ_GET_REPORT)
> hid_input_report(hid, report->type, buf, ret, 0);
>
> + ret = 0;
> +
> out:
> kfree(buf);
> + return ret;
> }
> EXPORT_SYMBOL_GPL(__hid_request);
>
> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> index 1fce0076e7dc..fadf76f0a386 100644
> --- a/drivers/hid/hid-input.c
> +++ b/drivers/hid/hid-input.c
> @@ -1542,52 +1542,71 @@ static void hidinput_close(struct input_dev *dev)
> hid_hw_close(hid);
> }
>
> -static void hidinput_change_resolution_multipliers(struct hid_device *hid)
> +static bool __hidinput_change_resolution_multipliers(struct hid_device *hid,
> + struct hid_report *report, bool use_logical_max)
> {
> - struct hid_report_enum *rep_enum;
> - struct hid_report *rep;
> struct hid_usage *usage;
> + bool update_needed = false;
> int i, j;
>
> - rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
> - list_for_each_entry(rep, &rep_enum->report_list, list) {
> - bool update_needed = false;
> + if (report->maxfield == 0)
> + return false;
>
> - if (rep->maxfield == 0)
> - continue;
> + /*
> + * If we have more than one feature within this report we
> + * need to fill in the bits from the others before we can
> + * overwrite the ones for the Resolution Multiplier.
> + */
> + if (report->maxfield > 1) {
> + hid_hw_request(hid, report, HID_REQ_GET_REPORT);
> + hid_hw_wait(hid);
> + }
>
> - /*
> - * If we have more than one feature within this report we
> - * need to fill in the bits from the others before we can
> - * overwrite the ones for the Resolution Multiplier.
> + for (i = 0; i < report->maxfield; i++) {
> + __s32 value = use_logical_max ?
> + report->field[i]->logical_maximum :
> + report->field[i]->logical_minimum;
> +
> + /* There is no good reason for a Resolution
> + * Multiplier to have a count other than 1.
> + * Ignore that case.
> */
> - if (rep->maxfield > 1) {
> - hid_hw_request(hid, rep, HID_REQ_GET_REPORT);
> - hid_hw_wait(hid);
> - }
> + if (report->field[i]->report_count != 1)
> + continue;
>
> - for (i = 0; i < rep->maxfield; i++) {
> - __s32 logical_max = rep->field[i]->logical_maximum;
> + for (j = 0; j < report->field[i]->maxusage; j++) {
> + usage = &report->field[i]->usage[j];
>
> - /* There is no good reason for a Resolution
> - * Multiplier to have a count other than 1.
> - * Ignore that case.
> - */
> - if (rep->field[i]->report_count != 1)
> + if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER)
> continue;
>
> - for (j = 0; j < rep->field[i]->maxusage; j++) {
> - usage = &rep->field[i]->usage[j];
> + *report->field[i]->value = value;
> + update_needed = true;
> + }
> + }
> +
> + return update_needed;
> +}
>
> - if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER)
> - continue;
> +static void hidinput_change_resolution_multipliers(struct hid_device *hid)
> +{
> + struct hid_report_enum *rep_enum;
> + struct hid_report *rep;
> + int ret;
>
> - *rep->field[i]->value = logical_max;
> - update_needed = true;
> + rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
> + list_for_each_entry(rep, &rep_enum->report_list, list) {
> + bool update_needed = __hidinput_change_resolution_multipliers(hid,
> + rep, true);
> +
> + if (update_needed) {
> + ret = __hid_request(hid, rep, HID_REQ_SET_REPORT);
> + if (ret) {
> + __hidinput_change_resolution_multipliers(hid,
> + rep, false);
> + return;
> }
> }
> - if (update_needed)
> - hid_hw_request(hid, rep, HID_REQ_SET_REPORT);
> }
>
> /* refresh our structs */
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index ac0c70b4ce10..5a24ebfb5b47 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -894,7 +894,7 @@ struct hid_field *hidinput_get_led_field(struct hid_device *hid);
> unsigned int hidinput_count_leds(struct hid_device *hid);
> __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code);
> void hid_output_report(struct hid_report *report, __u8 *data);
> -void __hid_request(struct hid_device *hid, struct hid_report *rep, int reqtype);
> +int __hid_request(struct hid_device *hid, struct hid_report *rep, int reqtype);
> u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags);
> struct hid_device *hid_allocate_device(void);
> struct hid_report *hid_register_report(struct hid_device *device,
> --
> 2.19.2
>