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

Benjamin Tissoires
2019-04-23T15:46:31Z

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>
---
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