Repeated connect/disconnect cycles under GNOME can trigger an occasional
OOPS from within e.g. wacom_led_select_store, presumably due to a timing
issue where userspace begins setting a value immediately before the
device disconnects and our shared data is whisked away.
Signed-off-by: Jason Gerecke <killertofu@xxxxxxxxx>
---
Changes in v2:
* Added in missing escape character
drivers/hid/wacom_sys.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 8593047..265429b 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -641,6 +641,9 @@ static ssize_t wacom_led_select_store(struct device *dev, int set_id,
unsigned int id;
int err;
+ if (!wacom)
+ return -ENODEV;
+
err = kstrtouint(buf, 10, &id);
if (err)
return err;
@@ -666,6 +669,8 @@ static ssize_t wacom_led##SET_ID##_select_show(struct device *dev, \
{ \
struct hid_device *hdev = container_of(dev, struct hid_device, dev);\
struct wacom *wacom = hid_get_drvdata(hdev); \
+ if (!wacom) \
+ return -ENODEV; \
return scnprintf(buf, PAGE_SIZE, "%d\n", \
wacom->led.select[SET_ID]); \
} \
@@ -702,7 +707,8 @@ static ssize_t wacom_##name##_luminance_store(struct device *dev, \
{ \
struct hid_device *hdev = container_of(dev, struct hid_device, dev);\
struct wacom *wacom = hid_get_drvdata(hdev); \
- \
+ if (!wacom) \
+ return -ENODEV; \
return wacom_luminance_store(wacom, &wacom->led.field, \
buf, count); \
} \
@@ -710,6 +716,8 @@ static ssize_t wacom_##name##_luminance_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct wacom *wacom = dev_get_drvdata(dev); \
+ if (!wacom) \
+ return -ENODEV; \
return scnprintf(buf, PAGE_SIZE, "%d\n", wacom->led.field); \
} \
static DEVICE_ATTR(name##_luminance, DEV_ATTR_RW_PERM, \
@@ -729,6 +737,9 @@ static ssize_t wacom_button_image_store(struct device *dev, int button_id,
unsigned len;
u8 xfer_id;
+ if (!wacom)
+ return -ENODEV;
+
if (hdev->bus == BUS_BLUETOOTH) {
len = 256;
xfer_id = WAC_CMD_ICON_BT_XFER;
--
2.1.2
--
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